1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
|
<!doctype HTML public "-//W3O//DTD W3 HTML 3.2//EN">
<HTML>
<HEAD>
<TITLE>The Fetchmail FAQ</TITLE>
<link rev=made href="mailto:esr@snark.thyrsus.com">
<meta name="description" content="Frequently asked questions about fetchmail.">
<meta name="keywords" content="fetchmail, POP, POP2, POP3, IMAP, remote mail">
</HEAD>
<BODY>
<table width="100%" cellpadding=0><tr>
<td width="30%">Back to <a href="index.html">Fetchmail Home Page</a>
<td width="30%" align=center>To <a href="/~esr/sitemap.html">Site Map</a>
<td width="30%" align=right>$Date: 1998/06/05 06:08:35 $
</table>
<HR>
<H1>Frequently Asked Questions About Fetchmail</H1>
Before reporting any bug, please read <a href="#G3">G3</a> for advice
on how to include diagnostic information that will get your bug fixed
as quickly as possible. <p>
If you have a question or answer you think ought to be added to this FAQ list,
mail it to fetchmail's maintainer, Eric S. Raymond, at
<A HREF="mailto:esr@thyrsus.com">esr@snark.thyrsus.com</A>.<p>
<h1>General questions:</h1>
<a href="#G1">G1. What is fetchmail and why should I bother?</a><br>
<a href="#G2">G2. Where do I find the latest FAQ and fetchmail sources?</a><br>
<a href="#G3">G3. I think I've found a bug. Will you fix it?</a><br>
<a href="#G4">G4. I have this idea for a neat feature. Will you add it?</a><br>
<a href="#G5">G5. Is there a mailing list for exchanging tips?</a><br>
<a href="#G6">G6. So, what's this I hear about a fetchmail paper?</a><br>
<a href="#G7">G7. What is the best server to use with fetchmail?</a><br>
<a href="#G8">G8. How can I avoid sending my password en clair?</a><br>
<a href="#G9">G9. Is any special configuration needed to use a dynamic
IP address?</a><br>
<a href="#G10">G10. Is any special configuration needed to use firewalls?</a><br>
<h1>Build-time problems:</h1>
<a href="#B1">B1. Lex bombs out while building the fetchmail lexer.</a><br>
<a href="#B2">B2. I get link failures when I try to build fetchmail.</a><br>
<h1>Fetchmail configuration file grammar questions:</h1>
<a href="#F1">F1. Why does my old .fetchmailrc no longer work?</a><br>
<a href="#F2">F2. The .fetchmailrc parser won't accept my all-numeric user name.</a><br>
<a href="#F3">F3. The .fetchmailrc parser won't accept my host or username beginning with `no'.</a><br>
<a href="#F4">F4. I'm migrating from popclient. How do I need to modify my .poprc?</a><br>
<a href="#F5">F5. I'm getting a `parse error' message I don't understand.</a><br>
<h1>Configuration questions:</h1>
<a href="#C1">C1. Why do I need a .fetchmailrc when running as root on my own machine?</a><br>
<a href="#C2">C2. How can I arrange for a fetchmail daemon to get killed when I log out?</a><br>
<a href="#C3">C3. How do I know what interface and address to use with --interface?</a><br>
<a href="#C4">C4. How can I get fetchmail to work with ssh?</a><br>
<a href="#C5">C5. How can I set up support for sendmail's anti-spam 571 response?</a><br>
<h1>How to make fetchmail play nice with other software:</h1>
<a href="#T1">T1. How can I use fetchmail with sendmail?</a><br>
<a href="#T2">T2. How can I use fetchmail with qmail?</a><br>
<a href="#T3">T3. How can I use fetchmail with exim?</a><br>
<a href="#T4">T4. How can I use fetchmail with smail?</a><br>
<a href="#T5">T5. How can I use fetchmail with SCO's MMDF?</a><br>
<a href="#T6">T6. How can I use fetchmail with Lotus Notes?</a><br>
<a href="#T7">T7. How can I use fetchmail with Microsoft Exchange?</a><br>
<a href="#T8">T8. How can I use fetchmail with Compuserve RPA?</a><br>
<a href="#T9">T9. How can I use fetchmail with usa.net's servers?</a><br>
<a href="#T10">T10. How can I use fetchmail with HP OpenMail?</a><br>
<a href="#T11">T11. How can I use fetchmail with SOCKS?</a><br>
<a href="#T12">T12. How can I use fetchmail with IPv6 and IPsec?</a><br>
<h1>Runtime fatal errors:</h1>
<a href="#R1">R1. Fetchmail's initial gethostbyname call fails on my host.</a><br>
<a href="#R2">R2. Fetchmail isn't working, and -v shows `SMTP connect failed' messages.</a><br>
<a href="#R3">R3. When I try to configure an MDA, fetchmail doesn't work.</a><br>
<a href="#R4">R4. Fetchmail dumps core when given an invalid rc file.</a><br>
<a href="#R5">R5. Fetchmail dumps core in -V mode, but operates normally otherwise.</a><br>
<a href="#R6">R6. Fetchmail dumps core when I use a .netrc file but works otherwise.</a><br>
<a href="#R7">R7. Running fetchmail in daemon mode doesn't work.</a><br>
<a href="#R8">R8. Fetchmail hangs when used with pppd.</a><br>
<a href="#R9">R9. Fetchmail randomly dies with socket errors.</a><br>
<h1>Disappearing mail</h1>
<a href="#D1">D1. I think I've set up fetchmail correctly, but I'm not getting any mail.</a><br>
<a href="#D2">D2. All my mail seems to disappear after an interrupt.</a><br>
<a href="#D3">D3. Mail that was being fetched when I interrupted my fetchmail seems to have been vanished.</a></br>
<h1>Multidrop-mode problems:</h1>
<a href="#M1">M1. I've declared local names, but all my multidrop mail is going to root anyway.</a><br>
<a href="#M2">M2. I can't seem to get fetchmail to route to a local domain properly.</a><br>
<a href="#M3">M3. I tried to run a mailing list using multidrop, and I have a mail loop!</a><br>
<a href="#M4">M4. My multidrop fetchmail seems to be having DNS problems.</a><br>
<a href="#M5">M5. I'm seeing long DNS delays before each message is processed.</a><br>
<a href="#M6">M6. How do I get multidrop mode to work with majordomo?</a>
<h1>Mangled mail:</h1>
<a href="#X1">X1. Spurious blank lines are appearing in the headers of fetched mail.</a><br>
<a href="#X2">X2. My mail client can't see a Subject line.</a><br>
<a href="#X3">X3. Messages containing "From" at start of line are being split.</a><br>
<a href="#X4">X4. My mail is being mangled in a new and different way.</a><br>
<a href="#X5">X5. Using POP3, retrievals seems to be fetching too much!</a><br>
<h1>Other Problems:</h1>
<a href="#O1">O1. The --logfile option doesn't work if the logfile doesn't exist.</a><br>
<a href="#O2">O2. Every time I get a POP or IMAP message the header is
dumped to all my terminal sessions.</a><br>
<a href="#O3">O3. Does fetchmail reread its rc file every poll cycle?</a><br>
<a href="#O4">O4. Why do deleted messages show up again when I take
a line hit while downloading?</a><br>
<a href="#O5">O5. Why is fetched mail being logged with my name, not the real From address?</a><br>
<a href="#O6">O6. I'm seeing long sendmail delays at start of each poll cycle.</a><br>
<a href="#O7">O7. Why doesn't fetchmail deliver mail in date-sorted order?</a><br>
<h1>Answers:</h1>
<hr>
<h2><a name="G1">G1. What is fetchmail and why should I bother?</a></h2>
Fetchmail is a one-stop solution to the remote mail retrieval problem
for Unix machines, quite useful to anyone with an intermittent PPP or
SLIP connection to a remote mailserver. It can collect mail using any
variant of POP or IMAP and forwards via port 25 to the local SMTP
listener, enabling all the normal forwarding/filtering/aliasing
mechanisms that would apply to local mail or mail arriving via a
full-time TCP/IP connection.<p>
Fetchmail is not a toy or a coder's learning exercise, but an
industrial-strength tool capable of transparently handling every
retrieval demand from those of a simple single-user ISP connection up
to mail retrieval and rerouting for an entire client domain.
Fetchmail is easy to configure, unobtrusive in operation, powerful,
feature-rich, and well documented. Extensive testing by a large,
multi-platform user community has shown that fetchmail is as near
bulletproof as the underlying protocols permit.<p>
If you found this FAQ in the distribution, see the README for fetchmail's
full feature list.<p>
<hr>
<h2><a name="G2">G2. Where do I find the latest FAQ and fetchmail
sources?</a></h2>
The latest HTML FAQ is available alongside the latest fetchmail
sources at the fetchmail home page:
<a href="http://www.tuxedo.org/~esr/fetchmail">
http://www.tuxedo.org/~esr/fetchmail</a>. You can also find
both in the <a
href="http://sunsite.unc.edu/pub/Linux/system/mail/pop/!INDEX.html">POP
mail tools directory on Sunsite</a>.<p>
A text dump of this FAQ is included in the fetchmail
distribution. Because it freezes at distribution release time, it may
not be completely current.<p>
<hr>
<h2><a name="G3">G3. I think I've found a bug. Will you fix it?</a></h2>
Yes I will, provided you include enough diagnostic information for me
to go on. Send bugs to <a
href="mailto:fetchmail-friends@ccil.org">fetchmail-friends</a>. When reporting
bugs, please include the following:
<ol>
<li>Your operating system and compiler version.
<li>The name and version of the SMTP listener or MDA you are forwarding to.
<li>Any command-line options you used.
<li>The output of fetchmail -V called with whatever other
command-line options you used.
</ol>
Often, the first thing I will do when you report a bug is tell you to
upgrade to the newest version, and then see if the problem reproduces.
So you'll probably save us both time if you upgrade and test with
the latest version <em>before</em> sending in a bug report.<P>
It is helpful if you include your .fetchmailrc, but not necessary
unless your symptom seems to involve an error in configuration parsing.<p>
If fetchmail seems to run and fetch mail, but the headers look mangled
(that is headers are missing, or blank lines are inserted in the
headers) then read the FAQ items in section <a href="#X1">X</a>
before submitting a bug report. Pay special attention to the item on
<a href="#generic_mangling">diagnosing mail mangling</a>. There are
lots of ways for other programs in the mail chain to screw up that
look like fetchmail's fault, but you may be able to fix these by
tweaking your configuration.<P>
A transcript of the failed session with -v on is almost always useful.
It is very important that the transcript include your POP/IMAP server's
greeting line, so I can identify it in case of server problems.<P>
If the bug involves a core dump or hang, a gdb stack trace is good to have.
(Bear in mind that you can attach gdb to a running but hung process by
giving the process ID as a second argument.) You will need to
reconfigure with <p>
<LISTING>
CFLAGS=-g LDFLAGS=" " ./configure
</LISTING>
and then rebuild in order to generate a version that can be gdb-traced.<p>
Best of all is a mail file which, when fetched, will reproduce the
bug under the latest (current) version.<p>
Any bug I can reproduce will usually get fixed very quickly, often
within 48 hours. Bugs I can't reproduce are a crapshoot. If the
solution isn't obvious when I first look, it may evade me for a long
time (or to put it another way, fetchmail is well enough tested that the
easy bugs have long since been found). So if you want your bug fixed
rapidly, it is not just sufficient but nearly <em>necessary</em> that
you give me a way to reproduce it.<p>
<hr>
<h2><a name="G4">G4. I have this idea for a neat feature. Will you add it?</a></h2>
Probably not. Most of the feature suggestions I get are for ways to
set various kinds of administrative policy or add more spam filtering
(the most common one, which I used to get about four million times a week
and got <em>really</em> tired of, is for tin-like kill files).<p>
You can do spam filtering better with procmail or mailagent on the
server side and (if you're the server sysadmin) sendmail.cf domain
exclusions. You can do other policy things better with the
<CODE>mda</CODE> option and script wrappers around fetchmail. If
it's a prime-time-vs.-non-prime-time issue, ask yourself whether a
wrapper script called from crontab would do the job.<p>
I'm not going to do these; fetchmail's job is transport, not policy, and I
refuse to change it from doing one thing well to attempting many things badly.
One of my objectives is to keep fetchmail simple so it stays reliable.<p>
Furthermore, since about version 4.3.0 fetchmail has passed out of active
development and been essentially stable. It is no longer my top
project, and I am going to be quite reluctant to add features that
might either jeopardize its stability or or involve me in large
amounts of coding.<p>
All that said, if you have a feature idea that really is about a transport
problem that can't be handled anywhere but fetchmail, lay it on me. I'm
very accommodating about good ideas.<p>
<hr>
<h2><a name="G5">G5. Is there a mailing list for exchanging tips?</a></h2>
There is a fetchmail-friends list for people who want to discuss fixes
and improvements in fetchmail and help co-develop it. It's at <a
href="mailto:fetchmail-friends@thyrsus.com">fetchmail-friends@thyrsus.com</a>.
There is also an announcements-only list, <em>fetchmail-announce@thyrsus.com</em>.<P>
Both lists are SmartList reflectors; sign up in the usual way with a
message containing the word "subscribe" in the subject line sent to
<a href="mailto:fetchmail-friends-request@thyrsus.com?subject=subscribe">
fetchmail-friends-request@thyrsus.com</a> or
<a href="mailto:fetchmail-announce-request@thyrsus.com?subject=subscribe">
fetchmail-announce-request@thyrsus.com</a>. (Similarly, "unsubscribe"
in the Subject line unsubscribes you, and "help" returns general list help) <p>
<hr>
<h2><a name="G6">G6. So, what's this I hear about a fetchmail paper?</a></h2>
Now it can be told! The fetchmail development was also a sociological
experiment, an extended test to see if my theory about the critical
features of the Linux development model is correct.<p>
The experiment was a success. I wrote a paper about it titled <a
href="http://www.tuxedo.org/~esr/writings/cathedral.html">The
Cathedral and the Bazaar</a> which was first presented at Linux
Kongress '97 in Bavaria and very well received there. It was also
given at Atlanta Linux Expo, Linux Pro '97 in Warsaw, and the first
Perl Conference, at UniForum '98, and will be the basis of an invited
presentation at Usenix '98. The folks at Netscape tell me it helped
them decide to <a
href="http://www.netscape.com/newsref/pr/newsrelease558.html"> give
away the source for Netscape Communicator</a>).<p>
If you're reading a non-HTML dump of this FAQ, you can find the paper
on the Web with a search for that title.<p>
<hr>
<h2><a name="G7">G7. What is the best server to use with fetchmail?</a></h2>
Fetchmail will work with any POP, IMAP, or ESMTP/ETRN server that
conforms to the relevant RFCs (and even some oughtright broken ones
like Microsoft Exchange). This doesn't mean it works equally well
with all, however. POP2 servers, and POP3 servers without LAST, limit
fetchmail's capabilities in various ways described on the manual
page.<P>
Most modern Unixes (and effectively all Linux/*BSD systems) come with
POP3 support preconfigured (but beware of the horribly broken POP3
server mentioned in <a href="#D2">D2</a>). An increasing minority
also feature IMAP (you can detect IMAP support by running fetchmail in
AUTO mode).<P>
If you have the option, we recommend using or installing IMAP4rev1; it has
the best facilities for tracking message `seen' states. It also
recovers from interrupted connections more gracefully than POP3, and
enables some significant performance optimizations.<P>
You can find sources for IMAP software at <a
href="http://www.imap.org"> The IMAP Connection</a>; we like the
open-source UW IMAP and Cyrus products. UW IMAP is the reference
implementation of IMAP.<P>
<hr>
<h2><a name="G8">G8. How can I avoid sending my password en clair?</a></h2>
Depending on what your mail server you are talking to, this ranges
from trivial to impossible. It may even be next to useless.<P>
Most people use fetchmail over phone wires, which are hard to tap.
Anybody with the skill and resources to do this could get into your
server mailbox with much less effort by subverting the server host.
So if your provider setup is modem wires going straight into a service
box, you probably don't need to worry.<P>
In general there is little point in trying to secure your fetchmail
transaction unless you trust the security of the server host you are
retrieving mail from. Your vulnerability is more likely to be an
insecure local network on the server end (e.g. to somebody with a TCP/IP
packet sniffer intercepting Ethernet traffic between the modem
concentrator you dial in to and the mailserver host).<P>
Having realized this, you need to ask whether password encryption
alone will really address your security exposure. If you think you
might be snooped, it's better to use end-to-end encryption on your
whole mail stream so none of it can be read. One of the advantages of
fetchmail over conventional SMTP-push delivery is that you may be able
to arrange this by using ssh(1); see <a href="#C4">C4</a>.<P>
If ssh/sshd isn't available, or you find it too complicated for you to
set up, password encryption will at least keep a malicious cracker
from deleting your mail, and require him to either tap your connection
continuously or crack root on the server in order to read it.<P>
You can deduce what encryptions your mail server has available by
by looking at the server greeting line (and, for IMAP, the
response to a CAPABILITY query). Do a <code>fetchmail -v</code>
to see these, or telnet direct to the server port (110 for POP3, 143 for
IMAP).<P>
The facility you are most likely to have available is APOP. This is a
POP3 feature supported by many servers. If you see something in the
greeting line that looks like an angle-bracket-enclosed Internet
address with a numeric left-hand part, that's an APOP challenge (it
will vary each time you log in). You can register a secret on the
host (using <code>popauth(8)</code> or some program like it). Specify
the secret as your password in your .fetchmailrc; it will be used to
encrypt the current challenge, and the encrypted form will be sent
back the the server for verification.<P>
Alternatively, you may have Kerberos available. This may require you
to set up some magic files in your home directory on your client
machine, but means you can omit specifying any password at all.<P>
Fetchmail supports two different Kerberos schemes. One is a
POP3 variant called KPOP; consult the documentation of your mail
server to see if you have it (one clue is the string "krb-IV" in the
greeting line on port 110). The other is an IMAP facility described
by RFC1731. You can tell if this one is present by looking for
AUTH=KERBEROS_V4 in the CAPABILITY response.<P>
If you are fetching mail from a CompuServe POP3 account, you can use
their RPA authentication (which works much like APOP). See <a
href="#T7">T7</a> for details.<P>
Your POP3 server may have the RFC1938 OTP capability to use one-time
passwords (if it doesn't, you can get OTP patches for the 2.2 version
of the Qualcomm popper from <a href="#cmetz">Craig Metz</a>). To check
this, look for the string "otp-" in the greeting line. If you see it,
and your fetchmail was built with OPIE support compiled in (see the
distribution INSTALL file), fetchmail will detect it also. When using
OTP, you will specify a password but it will not be sent en clair.<P>
Sadly, there is at present (May 1998) no OTP or APOP-like
facility generally available on IMAP servers. However, there do exist
patches which will OTP-enable the University of Washington IMAP
daemon, version 4.1-BETA.<P>
You can get both POP3 and IMAP OTP patches from <a name="cmetz">Craig
Metz</A>, over FTP via either
<a href="ftp://ftp.inner.net/pub/opie/patches">
ftp://ftp.inner.net/pub/opie/patches</a> (IPv4) or
<a href="ftp://ftp.ipv6.inner.net/pub/opie/patches">
ftp://ftp.ipv6.inner.net/pub/opie/patches</a> (IPv6).<P>
These patches use a SASL authentication method named "X-OTP" because there is
not currently a standard way to do this; fetchmail also uses this method, so
the two will interoperate happily. They better, because this is how Craig gets
his mail ;-)<P>
(One important win of OTP is that it's not subject to ITAR restrictions.)<P>
<hr>
<h2><a name="G9">G9. Is any special configuration needed to use a dynamic IP address?</a></h2>
Yes. In order to avoid giving indigestion to certain picky MTAs
(notably <a href="#T3">exim</a>), fetchmail always makes the RCPT TO
address it feeds the MTA a fully qualified one with a hostname part.
Normally it does this by appending @ and your client machine's
hostname.<P>
This, however, can create problems when fetchmail is running in daemon
mode and outlasts the dynamic IP address assignment your client
machine had when it started up.<P>
Since the new IP address (looked up at RCPT TO interpretation time)
doesn't match the original, the most benign possible result is that
your MTA thinks it's seeing a relaying attempt and refuses. More
frequently, fetchmail will try to connect to a nonexistent host
address and time out. Worst case, you could up forwarding your mail
to the wrong machine!<P>
Use the <code>smtpaddress</code> option to force the appended hostname
to one with a (fixed) IP address of 127.0.0.1 in your
<code>/etc/hosts</code>. (The name `localhost' will usually work; or
you can use the IP address itself).<P>
Only one fetchmail option interacts directly with your IP address,
`<code>interface</code>'. This option can be used to set the gateway
device and restrict the IP address range fetchmail will use. Such a
restriction is sometimes useful for security reasons, especially on
multihomed sites. See <a href="http:#C3">C3</a>.<P>
I recommend against trying to set up the <code>interface</code> option
when initially developing your poll configuration -- it's never
necessary to do this just to get a link working. Get the link working
first, observe the actual address range you see on connections, and
add an <code>interface</code> option (if you need one) later.<P>
If you're using a dynamic-IP configuration, one other (non-fetchmail)
problem you may run into with outgoing mail is that some sites will
bounce your email because the hostname your giving them isn't real
(and doesn't match what they get doing a reverse DNS on your
dynamically-assigned IP address). If this happens, you need to hack
your sendmail so it masquerades as your host. Setting<P>
<pre>
DMsmarthost.here
</pre>
in your <code>sendmail.cf</code> will work, or you can set<P>
<pre>
MASQUERADE_AS(smarthost.here)
</pre>
in the m4 configuration and do a reconfigure. (In both cases, replace
<code>smarthost.here</code> with the actual name of your mailhost.)
See the <a href="http://www.lege.com/sendmail-FAQ.txt">sendmail
FAQ</a> for more details.<P>
<hr>
<h2><a name="G10">G10. Is any special configuration needed to use firewalls?</a></h2>
No. You can use fetchmail with SOCKS, the standard tool for
indirecting TCP/IP through a firewall. You can find out about SOCKS,
and download the SOCKS software including server and client code, at
the <a href="http://www.socks.nec.com/">SOCKS distribution
site</a>.)<P>
The specific recipe for using fetchmail with a firewall is at <a
href="#T11">T11</a><P>
<hr>
<h2><a name="B1">B1. Lex bombs out while building the fetchmail lexer.</a></h2>
In the immortal words of Alan Cox the last time this came up: ``Take
the Solaris lex and stick it up the backside of a passing Sun
salesman, then install <a
href="ftp://prep.ai.mit.edu/~ftp/pub/gnu">flex</a> and use that. All
will be happier.''<P>
I couldn't have put it better myself, and aren't going to try now.<P>
<hr>
<h2><a name="B2">B2. I get link failures when I try to build fetchmail.</a></h2>
If you get errors resembling these<P>
<pre>
mxget.o(.text+0x35): undefined referenceto `__res_search'
mxget.o(.text+0x99): undefined reference to`__dn_skipname'
mxget.o(.text+0x11c): undefined reference to`__dn_expand'
mxget.o(.text+0x187): undefined reference to`__dn_expand'
make: *** [fetchmail] Error 1
</pre>
then you must add "-lresolv" to the LOADLIBS line in your Makefile
once you have installed the `bind' package.<P>
<hr>
<h2><a name="F1">F1. Why does my old .fetchmailrc file no longer work?</a></h2>
<h3>If your file predates 4.0.6:</h3>
Just after the `<CODE>via</CODE>' option was introduced, I realized
that the interactions between the `<CODE>via</CODE>',
`<CODE>aka</CODE>', and `<CODE>localdomains</CODE>' options were out
of control. Their behavior had become complex and confusing, so much so
that I was no longer sure I understood it myself. Users were being
unpleasantly surprised.<P>
Rather than add more options or crock the code, I re-thought it. The
redesign simplified the code and made the options more orthogonal, but
may have broken some complex multidrop configurations.
Any multidrop configurations that depended on the name just after the
`<CODE>poll</CODE>' or `<CODE>skip</CODE>' keyword being still
interpreted as a DNS name for address-matching purposes, even in the
presence of a `<CODE>via</CODE>' option, will break.<P>
It is theoretically possible that other unusual configurations (such
as those using a non-FQDN poll name to generate Kerberos IV tickets) might
also break; the old behavior was sufficiently murky that we can't be
sure. If you think this has happened to you, contact the maintainer.<P>
<h3>If your file predates 3.9.5:</h3>
The `<code>remote</code>' keyword has been changed to `<code>folder</code>'.
If you try to use the old keyword, the parser will utter a warning.<P>
<h3>If your file predates 3.9:</h3>
It could be because you're using a .fetchmailrc that's written in the
old popclient syntax without an explicit `<CODE>username</CODE>'
keyword leading the first user entry attached to a server entry.
This error can be triggered by having a user option such as `<CODE>keep</CODE>'
or `<CODE>fetchall</CODE>' before the first explicit username. For
example, if you write<p>
<pre>
poll openmail protocol pop3
keep user "Hal DeVore" there is hdevore here
</pre>
the `<CODE>keep</CODE>' option will generate an entire user entry with
the default username (the name of fetchmail's invoking user).<p>
The popclient compatibility syntax was removed in 4.0. It complicated
the configuration file grammar and confused users.<p>
<h3>If your file predates 2.8:</h3>
The `<CODE>interface</CODE>', `<CODE>monitor</CODE>' and
`<CODE>batchlimit</CODE>' options changed after 2.8.<p>
They used to be global options with `<CODE>set</CODE>' syntax like the
batchlimit and logfile options. Now they're per-server options, like
`<CODE>protocol</CODE>'.<p>
If you had something like<p>
<pre>
set interface = "sl0/10.0.2.15"
</pre>
in your .fetchmailrc file, simply delete that line and insert
`interface sl0/10.0.2.15' in the server options part of your `defaults'
declaration.<p>
Do similarly for any `<CODE>monitor</CODE>' or `<CODE>batchlimit</CODE>' options.<p>
<hr>
<h2><a name="F2">F2. The .fetchmailrc parser won't accept my all-numeric user name.</a></h2>
So put string quotes around it. :-)<p>
The configuration file parser treats any all-numeric token as a
number, which will confuse it when it's expecting a name. String
quoting forces the token's class.<p>
<hr>
<h2><a name="F3">F3. The .fetchmailrc parser won't accept my host or username beginning with `no'.</a></h2>
You're caught in an unfortunate crack between the newer-style syntax
for negated options (`no keep', `no rewrite' etc.) and the older style
run-on syntax (`nokeep', `norewrite' etc.).<p>
You can work around this easily. Just put string quotes around your
token.<p>
I haven't fixed this because there is no good fix for it short of
implementing a token pushback stack in the lexer. That's more
additional complexity than I'm willing to add to banish a very
marginal bug with an easy workaround.<p>
<hr>
<h2><a name="F4">F4. I'm migrating from popclient. How do I need to modify my .poprc?</a></h2>
If you have been using popclient (the ancestor of this program)
at version 3.0b6 or later, start with this<p>
<pre>
(cd; mv .poprc .fetchmailrc)
</pre>
and do <code>fetchmail -V</code> to see if fetchmail's parser understands
your configuration.<p>
Be aware that some of popclient's unnecessary options have been
removed (see the NOTES file in the distribution for explanation). You
can't deliver to a local mail file or to standard output any more, and
using an MDA for delivery is discouraged. If you throw those options
away, fetchmail will now forward your mail into your system's normal
Internet-mail delivery path.<p>
Actually, using an MDA is now almost always the wrong thing; the MDA
facility has been retained only for people who can't or won't run a
sendmail-like SMTP listener on port 25. The default, SMTP forwarding
to port 25, is better for at least three major reasons. One: it feeds
retrieved POP and IMAP mail into your system's normal delivery path
along with local mail and normal Internet mail, so all your normal
filtering/aliasing/forwarding setup for local mail works. Two:
because the port 25 listener returns a positive acknowledge, fetchmail
can be sure you're not going to lose mail to a disk-full or some other
resource-exhaustion problem. Three: it means fetchmail doesn't have
to know where the system mailboxes are, or futz with file locking
(which makes two fewer places for it to potentially mess up).<p>
If you used to use <CODE>-mda "procmail -d</CODE>
<em><you></em><CODE>"</CODE> or something similar, forward to port
25 and do "<CODE>| procmail -d</CODE> <em><you></em><CODE>"</CODE> in
your ~/.forward file.<p>
As long as your new .fetchmailrc file does not use the removed
`localfolder' option or `<CODE>limit</CODE>' (which now takes a
maximum byte size rather than a line count), a straight move or copy
of your .poprc will often work. (The new run control file syntax also
has to be a little stricter about the order of options than the old,
in order to support multiple user descriptions per server; thus you
may have to rearrange things a bit.)<p>
Run control files in the minimal .poprc format (without the `username'
token) will trigger a warning. To eliminate this warning, add the
`<CODE>username</CODE>' keyword before your first user entry per server (it is
already required before second and subsequent user entries per server.<p>
In some future version the `<CODE>username</CODE>' keyword will be required.<p>
<hr>
<h2><a name="F5">F5. I'm getting a `parse error' message I don't understand.</a></h2>
The most common cause of mysterious parse errors is putting a server
option after a user option. Check the manual page; you'll probably
find that by moving one or more options closer to the `poll' keyword
you can eliminate the problem.<p>
Yes, I know these ordering restrictions are hard to understand.
Unfortunately, they're necessary in order to allow the `defaults'
feature to work.<P>
<hr>
<h2><a name="C1">C1. Why do I need a .fetchmailrc when running as root on my own machine?</a></h2>
Ian T. Zimmerman <itz@rahul.net> asked:<p>
On the machine where I'm the only real user, I run fetchmail as root
from a cron job, like this:<p>
<pre>
fetchmail -u "itz" -p POP3 -s bolero.rahul.net
</pre>
This used to work as is (with no .fetchmailrc file in root's home
directory) with the last version I had (1.7 or 1.8, I don't
remember). But with 2.0, it RECPs all mail to the local root user,
unless I create a .fetchmailrc in root's home directory containing:<p>
<pre>
skip bolero.rahul.net proto POP3
user itz is itz
</pre>
It won't work if the second line is just "<CODE>user itz</CODE>". This is silly.<p>
It seems fetchmail decides to RECP the `default local user' (ie. the
uid running fetchmail) unless there are local aliases, and the
`default' aliases (itz->itz) don't count. They should.<p>
Answer:<p>
No they shouldn't. I thought about this for a while, and I don't much
like the conclusion I reached, but it's unavoidable. The problem is
that fetchmail has no way to know, in general, that a local user `itz'
actually exists.<p>
"Ah!" you say, "Why doesn't it check the password file to see if the remote
name matches a local one?" Well, there are two reasons.<p>
One: it's not always possible. Suppose you have an SMTP host declared
that's not the machine fetchmail is running on? You lose.<p>
Two: How do you know server itz and SMTP-host itz are the same person?
They might not be, and fetchmail shouldn't assume they are unless
local-itz can explicitly produce credentials to prove it (that is, the
server-itz password in local-itz's .fetchmailrc file.).<p>
Once you start running down possible failure modes and thinking about
ways to tinker with the mapping rules, you'll quickly find that all the
alternatives to the present default are worse or unacceptably
more complicated or both.<p>
<hr>
<h2><a name="C2">C2. How can I arrange for a fetchmail daemon to get killed when I log out?</a></h2>
The easiest way to dispatch fetchmail on logout (which will work
reliably onlif you have just one login going at any time) is to
arrange for the command `fetchmail -q' to be called on logout. Under
bash, you can arrange this by putting `fetchmail -q' in the file
`~/.bash_logout'. Most csh variants execute `~/.logout' on logout.
For other shells, consult your shell manual page.<p>
Automatic startup/shutdown of fetchmail is a little harder to arrange
if you may have multiple login sessions going. In the contrib
subdirectory of the fetchmail distribution there is some shell code
you can add to your .bash_login and .bash_logout profiles that will
accomplish this. Thank James Laferriere <babydr@nwrain.net> for
it.<p>
<hr>
<h2><a name="C3">C3. How do I know what interface and address to use with --interface?</a></h2>
This depends a lot on your local networking configuration (and right
now you can't use it at all except under Linux). However, here are
some important rules of thumb that can help. If they don't work, ask
your local sysop or your Internet provider.<p>
First, you may not need to use --interface at all. If your machine
only ever does SLIP or PPP to one provider, it's almost certainly by a
point to point modem connection to your provider's local subnet that's
pretty secure against snooping (unless someone can tap your phone or
the provider's local subnet!). Under these circumstances, specifying
an interface address is fairly pointless.<p>
What the option is really for is sites that use more than one
provider. Under these circumstances, typically one of your provider
IP addresses is your mailserver (reachable fairly securely via the
modem and provider's subnet) but the others might ship your packets
(including your password) over unknown portions of the general
Internet that could be vulnerable to snooping. What you'll use
--interface for is to make sure your password only goes over the
one secure link.<p>
To determine the device:<p>
<ol>
<li> If you're using a SLIP link, the correct device is probably sl0.
<li> If you're using a PPP link, the correct device is probably ppp0.
<li> If you're using a direct connection over a local network such as
an ethernet, use the command `netstat -r' to look at your routing table.
Try to match your mailserver name to a destination entry; if you don't
see it in the first column, use the `default' entry. The device name
will be in the rightmost column.
</ol>
To determine the address and netmask:<p>
<ol>
<li> If you're talking to slirp, the correct address is probably 10.0.2.15,
with no netmask specified. (It's possible to configure slirp to present
other addresses, but that's the default.)
<li> If you have a static IP address, run `ifconfig <device>', where <device>
is whichever one you've determined. Use the IP address given after
"inet addr:". That is the IP address for your end of the link, and is
what you need. You won't need to specify a netmask.
<li> If you have a dynamic IP address, your connection IP will vary randomly
over some given range (that is, some number of the least significant bits
change from connection to connection). You need to declare an address
with the variable bits zero and a complementary netmask that sets
the range.
</ol>
To illustrate the rule for dynamic IP addresses, let's suppose you're
hooked up via SLIP and your IP provider tells you that the dynamic
address pool is 255 addresses ranging from 205.164.136.1 to
205.164.136.255. Then<p>
<pre>
interface "sl0/205.164.136.0/255.255.255.0"
</pre>
would work. To range over any value of the last two octets
(65536 addresses) you would use<p>
<pre>
interface "sl0/205.164.0.0/255.255.0.0"
</pre>
<hr>
<h2><a name="C4">C4. How can I get fetchmail to work with ssh?</a></h2>
We have two recipes for this. The first is a little easier to set up,
but only supports one user at a time.<P>
First, a lightly edited version of a recipe from Masafumi NAKANE:<p>
1. You must have ssh (the ssh client) on the local host and sshd (ssh
server) on the remote mail server. And you have to configure ssh so
you can login to the sshd server host without a password. (Refer to ssh
man page for several authentication methods.)<p>
2. Add something like following to your .fetchmailrc file: <p>
<pre>
poll mailhost port 1234 via localhost with proto pop3:
preconnect "ssh -f -L 1234:mailhost:110 mailhost sleep 20 </dev/null >/dev/null";
</pre>
(Note that 1234 can be an arbitrary port number. Privileged ports can
be specified only by root.) The effect of this ssh command is to
forward connections made to localhost port 1234 (in above example) to
mailhost's 110.<p>
This configuration will enable secure mail transfer. All the
conversation between fetchmail and remote pop server will be
encrypted.<p>
If sshd is not running on the remote mail server, you can specify
intermediate host running it. If you do this, however, communication
between the machine running sshd and the POP server will not be encrypted.
And the preconnect line would be like this:<p>
<pre>
preconnect "ssh -f -L 1234:mailhost:110 sshdhost sleep 20 </dev/null >/dev/null"
</pre>
You can work this trick with IMAP too, but the port number 110 in the
above would need to become 143.<p>
Second, a recipe from Charlie Brady <cbrady@ind.tansu.com.au>:<p>
Charlie says: "The [previous] recipe certainly works, but
the solution I post here is better in a few respects":
<UL>
<LI>this method will not fail if two or more users attempt to use fetchmail
simultaneously.
<LI>you are able to use the full facilities of tcpd to control access
<LI>this method does not depend on the preconnect feature of fetchmail, so
can be used for tunneling of other services as well.
</UL>
Here are the steps:
<OL>
<LI>
Make sure that the "socket" program is installed on the server
machine. Presently it lives at <a
href="ftp://sunsite.unc.edu/pub/linux/system/network/misc/socket-1.1.tar.gz">
ftp://sunsite.unc.edu/pub/linux/system/network/misc/socket-1.1.tar.gz</a>,
but watch out for a change in version number.<P>
<LI>
Set up an unprivileged account on your system with a .ssh directory
containing an SSH identity file "identity" with no pass phrase,
"identity.pub" and "known_hosts" containing the host key of your
mailhost. Let's call this account "noddy".
<LI>
On mailhost, set up no-password access for noddy@yourhost. Add to your
SSH authorised_keys file:
<PRE>
command="socket localhost 110",no-port-forwarding 1024 ......
</PRE>
where "<code>1024</code> ......" is the content of noddy's identity.pub file.
<LI>
Create a script /usr/local/bin/ssh.fm and make it executable:
<PRE>
#! /bin/sh
exec ssh -q -C -l your.login.id -e none mailhost socket localhost 110
</PRE>
<LI>
Add an entry in inetd.conf for whatever port you choose to use - say:
<PRE>
1234 stream tcp nowait noddy /usr/sbin/tcpd /usr/local/bin/ssh.fm
</PRE>
<LI>
Send a HUP signal to your inetd.
</OL>
Now just use localhost:1234 to access your POP server.<P>
<hr>
<h2><a name="C5">C5. How can I set up support for sendmail's anti-spam 571 response?</a></h2>
Rachel Polanskis <r.polanskis@nepean.uws.edu.au> writes:<p>
Basically you need to use the "check_*" rules in sendmail.
These are rules introduced since version 8.8.2<p>
The idea is to generate a list of domains and addresses that are placed into
a file - I call mine "sendmail.rej" and you place just one domain
or email address on each line. During the SMTP transaction, this file
is checked and if there is a match, the message is refused, with
a suitable "Service not available" message sent back to the sender.<p>
With the feature enabled in fetchmail, the mail is simply deleted,
with no further processing.<p>
The only drawback when blocking spam with fetchmail is that you
do not get the satisfaction of sending an error back to the sender.<p>
To actually use the check_mail rules in sendmail 8.8.2 or better,
you need to know how to generate a sendmail.cf file from the m4
config files distributed with sendmail.<p>
The actual rules can be found at the following URLS:<p>
<a href="http://www.informatik.uni-kiel.de/%7Eca/email/check.html">
http://www.informatik.uni-kiel.de/%7Eca/email/check.html</a><p>
This one is by Claus Aßman, who has documented more of sendmail then
I can digest!
Remember, when copying these rulesets off the web, that there are tabs
embedded in them, that may not be preserved. You <em>must</em> reintroduce
these tabs into the rules to make them work properly. <p>
Once you have your ruleset in place, and have generated a nice sendmail.cf
file, and the list of blocked sites, try telneting to your
SMTP port to test it, and send a message with a blocked address in it.<p>
You should see a message similar to:<p>
<pre>
"571 unsolicited email is refused"
</pre>
Next, if you have access to a host that you can send mail from, that
is <em>not</em> your mail host, add that host to your spamlist and
restart sendmail.<p>
Send a message to your mailing address from that host and then pop off
the message with fetchmail, using the -v argument. You can monitor
the SMTP transaction, and when the FROM address is parsed, if sendmail
sees that it is an address in spamlist, fetchmail will flush and
delete it.<p>
Under no circumstances put your <strong>mailhost</strong> or <strong>any host
you accept mail from</strong> using fetchmail into your reject file. You
<strong>will</strong> lose mail if you do this!!!<p>
The check_ rules work, and they work well. Coupled with fetchmail's
ability to respond to the appropriate error messages, you can be assured
of never seeing a spam from any address you put in the reject list.<p>
The only thing that is missing, as mentioned previously, is the ability
to allow sendmail to process the message further and generate an error
message to the sender. <p>
<hr>
<h2><a name="T1">T1. How can I use fetchmail with sendmail?</a></h2>
For most sendmails, no special configuration is required. Eric Allman
tells me that if <code>FEATURE(always_add_domain)</code> is included
in sendmail's configuration, you can leave the <code>rewrite</code>
option off.<P>
Günther Leber reports that Digital Unix sendmails won't work with
fetchmail. The symptom is an error message "<code>553 Local configuration
error, hostname not recognized as local</code>". The problem is that
fetchmail normally feeds sendmail with the client machine's host
address in the MAIL FROM line. These sendmails think this means
they're seeing the result of a mail loop and suppress the mail. You
may be able to work around this by running in <code>--invisible</code> mode.<P>
If you want to support multidrop mode, and you can get access to your
mailserver's sendmail.cf file, it's a good idea to add this rule:<P>
<pre>
H?l?Delivered-To: $u
</pre>
and declare `<CODE>envelope "Delivered-To:"</CODE>'. This will cause the
mailserver's sendmail to reliably write the appropriate envelope
address into each message before fetchmail sees it, and tell fetchmail
which header it is. With this change, multidrop mode should work
reliably even when the Received header omits the envelope address
(which will typically be the case when the message has multiple
recipients). <P>
<hr>
<h2><a name="T2">T2. How can I use fetchmail with qmail?</a></h2>
Turn on the <CODE>forcecr</CODE> option; qmail's listener mode doesn't like
header or message lines terminated with bare linefeeds.<p>
(This information is thanks to Robert de Bath
<robert@mayday.cix.co.uk>.)<p>
If a mailhost is using the qmail package (see <a
href="http://pobox.com/~djb/qmail.html">http://pobox.com/~djb/qmail.html</a>)
then, providing the local hosts are also using qmail, it is possible
to set up one fetchmail link to be reliably collect the mail for an
entire domain.<p>
One of the basic features of qmail is the `Delivered-To:' message
header. Whenever qmail delivers a message to a local mailbox it puts
the username and hostname of the envelope recipient on this line. The
major reason for this is to prevent mail loops. <p>
To set up qmail to batch mail for a disconnected site the ISP-mailhost
will have normally put that site in its `virtualhosts' control file so
it will add a prefix to all mail addresses for this site. This results
in mail sent to 'username@userhost.userdom.dom.com' having a
'Delivered-To:' line of the form:<p>
<pre>
Delivered-To: mbox-userstr-username@userhost.userdom.dom.com
</pre>
A single host maildrop will be slightly simpler:
<pre>
Delivered-To: mbox-userstr-username@userhost.dom.com
</pre>
The ISP can make the 'mbox-userstr-' prefix anything they choose
but a string matching the user host name is likely.<p>
To use this line you must:<p>
<ol>
<li>Ensure the option `envelope Delivered-To:' is in the fetchmail
config file.
<li>Ensure you have a localdomains containing 'userdom.dom.com' or
`userhost.dom.com' respectively.
</ol>
So far this reliably delivers messages to the correct machine of the
local network, to deliver to the correct user the 'mbox-userstr-'
prefix must be stripped off of the user name. This can be done by
setting up an alias within the qmail MTA on each local machine.
Simply create a dot-qmail file called '.qmail-mbox-userstr-default'
in the alias directory (normally /var/qmail/alias) with the contents:<p>
<pre>
| ../bin/qmail-inject -a -f"$SENDER" "${LOCAL#mbox-userstr-}@$HOST}"
</pre>
Note this <em>does</em> require a modern /bin/sh.<p>
Luca Olivetti adds:<P>
If you aren't using qmail locally, or you don't want to set up the
alias mechanism described above, you can use the option `<code>qvirtual
"mbox-userstr-"</code>' in your fetchmail config file to strip the prefix
from the local user name.<p>
<hr>
<h2><a name="T3">T3. How can I use fetchmail with exim?</a></h2><p>
By default, the exim listener enforces the the RFC1123 requirement
that MAIL FROM and RCPT TO addresses you pass to it have to be canonical
(e.g. with a fully qualified hostname part). <p>
Fetchmail always passes fully qualified RCPT TO addresses. But
MAIL FROM is a potential problem if the MTAs upstream from your fetchmail
don't necessarily pass canonicalized From and Return-Path addresses,
and fetchmail's <CODE>rewrite</CODE> option is off. The specific case
where this has come up involves bounce messages generated by sendmail
on your mailer host, which have the (un-canonicalized) origin address
MAILER-DAEMON.<p>
The right way to fix this is to enable the <CODE>rewrite</CODE> option and
have fetchmail canonicalize From and Return-Path addresses with the
mailserver hostname before exim sees them. This option is enabled by
default, so it won't be off unless you turned it off.<p>
If you must run with <CODE>rewrite</CODE> off, there is a switch in exim's
configuration files that allows it to accept domainless MAIL FROM
addresses; you will have to flip it by putting the line <p>
<pre>
sender_unqualified_hosts = localhost
</pre>
in the main section of the exim configuration file. Note that this
will result in such messages having an incorrect domain name attached
to their return address (your SMTP listener's hostname rather than
that of the remote mail server). <p>
<hr>
<h2><a name="T4">T4. How can I use fetchmail with smail?</a></h2><p>
Smail 3.2 is very nearly plug-compatible with sendmail, and may work
fine out of the box.<P>
We have one report that when processing multiple messages from a
single fetchmail session, smail sometimes delivers them in an
order other than received-date order. This can be annoying because it
scrambles conversational threads. This is not fetchmail's problem,
it is an smail `feature' and has been reported to the maintainers
as a bug.<P>
Very recent smail versions require an <code>-smtp_hello_verify</code>
option in the smail config file. This overrides smail's check to see
that the HELO address is actually that of the client machine, which
is never going to be the case when fetchmail is in the picture.
According to RFC1123 an SMTP listener <em>must</em> allow this
mismatch, so smail's new behavior (introduced sometime between
3.2.0.90 and 3.2.0.95) is a bug.<P>
<hr>
<h2><a name="T5">T5. How can I use fetchmail with SCO's MMDF?</a></h2><p>
We're told this is possible, but difficult and tricky (and we don't
have the recipe for it). Our informant suggests dropping MMDF and
using sendmail instead.<P>
<hr>
<h2><a name="T6">T6. How can I use fetchmail with Lotus Notes?</a></h2><p>
The Lotus Notes SMTP gateway tries to deduce when it should convert \n
to \r\n, but its rules are not the intuitive and correct-for-RFC822
ones. Use `forcecr'.<P>
<hr>
<h2><a name="T7">T7. How can I use fetchmail with Microsoft Exchange?</a></h2><p>
M$ Exchange violates the POP3 RFCs. Its LIST command does not reveal
the real sizes of mail in the pop mailbox, but the sizes of the
compressed versions in the exchange mail database (thanks to Arjan De
Vet and Guido Van Rooij for alerting us to this problem).<P>
Fetchmail works with M$ Exchange, despite this braindamage. Two
features are compromised. One is that the --limit option will not
work right (it will check against compressed and not actual sizes).
The other is that a too-small SIZE argument may be passed to your
ESMTP listener, assuming you're using one (this should not be a
problem unless the actual size of the message is above the listener's
configured length limit).<P>
If you want these fixed, go bug the Evil Empire. Or, better yet,
install a real operating system on your mailserver and run IMAP.<P>
<hr>
<h2><a name="T8">T8. How can I use fetchmail with CompuServe RPA?</a></h2>
First, make sure your fetchmail has the RPA support compiled in.
Stock fetchmail binaries (such as you might get from an RPM) don't.
You can check this by looking at the output of <code>fetchmail -V</code>;
if you see the string "+RPA" after the version ID you're good to go,
otherwise you'll have to build your own from sources (see the INSTALL
file in the source distribution for directions).<P>
Give your CompuServe pass-phrase in lower case as your password. Add
`@compuserve.com' to your user ID so that it looks like `user
<UserID>@compuserve.com', where <UserID> can be either
your numerical userID or your E-mail nickname. An RPA-enabled
fetchmail will automatically check for csi.com in the POP server's
greeting line. If that's found, it will query the server to see if it
is RPA-capable, and if so do an RPA transaction rather than a
plain-text password handshake.<P>
<strong>Warning:</strong> the verbose output of fetchmail will show
your pass-phrase in Unicode!<P>
<hr>
<h2><a name="T9">T9. How can I use fetchmail with usa.net's servers?</a></h2>
Enable `<CODE>fetchall</CODE>'. A user reports that the 2.2 version
of USA.NET's POP server reports that you must use the
`<CODE>fetchall</CODE>' option to make sure that all of the mail is
retrieved, otherwise some may be left on the server. This is almost
certainly a server bug.<P>
The usa.net servers (at least in their 2.2 version, June 1998) don't
handle the TOP command properly, either. Regardless of the argument
you give it, they retrieve only about 10 lines of the message.
Because fetchmail uses TOP for message retrieval (in order to avoid
marking messages seen), this is a problem. The `<CODE>keep</CODE>'
option causes fetchmail to use ordinary RETR, eliminating this
problem -- however, it also doesn't delete read mail. You may be able
to get around this by using the --keep and --flush options together.<P>
<hr>
<h2><a name="T10">T10. How can I use fetchmail with HP OpenMail?</a></h2>
No special configuration is required, but OpenMail has an annoying bug
similar to the big one in <a href="#T6">Microsoft Exchange</a>.
The message sizes it gives in the LIST are rounded to the nearest 1024
bytes. It also has a nasty habit of discarding headers it doesn't
recognize, such as X- and Resent- headers.<P>
As with M$ Exchange, the only real fix for these problems is to get a
POP (or preferably IMAP) server that isn't brain-dead.<P>
<hr>
<h2><a name="#T11">T11. How can I use fetchmail with SOCKS?</a></h2>
Daniel Sobral <<a href="mailto:dcs@gns.com.br">dcs@gns.com.br</a>
gave us the following recipe:<P>
<OL>
<LI> Install socks5. You don't need to have a socks server, you just
want the "runsocks" program.
<LI> Set the environment variable SOCKS_SERVER to the server you'll be
using. Alternatively, you may set SOCKS4_SERVER and/or
SOCKS5_SERVER. Eg:
<pre>
export SOCKS5_SERVER=socks.my.domain.com
</pre>
<LI> Set SOCKS5_USER and SOCKS5_PASSWD if needed.
<LI> Run fetchmail through runsocks. Just like this:
<pre>
runsocks fetchmail [parameters to fetchmail]
</pre>
</OL>
It wasn't that hard, was it? :-)<P>
<hr>
<h2><a name="T12">T12. How can I use fetchmail with IPv6 and IPsec?</a></h2>
To use fetchmail with IPv6, you need a system that supports IPv6, the "Basic
Socket Interface Extensions for IPv6" (RFC 2133), and the inet6-apps kit.
This currently means that you need to have a BSD/OS or NetBSD system with
the NRL IPv6+IPsec software distribution or a Linux system with the latest
experimental kernel and net-tools. It should not be hard to build fetchmail on
other IPv6 implementations if you can port the inet6-apps kit.<P>
To use fetchmail with network security (read: IPsec), you need a system that
supports IPsec, the API described in the "Network Security API for Sockets"
(draft-metz-net-security-api-01.txt), and the inet6-apps kit. This currently
means that you need to have a BSD/OS or NetBSD system with the NRL IPv6+IPsec
software distribution. A Linux IPsec implementation supporting this API will
probably appear in the coming months.<P>
The NRL IPv6+IPsec software distribution can be obtained from: <a
href="http://web.mit.edu/network/isakmp">http://web.mit.edu/network/isakmp</a>
<P>
The inet6-apps kit can be obtained from <a
href="ftp://ftp.ipv6.inner.net/pub/ipv6">ftp://ftp.ipv6.inner.net/pub/ipv6</a>
(via IPv6) or <a href="ftp://ftp.inner.net/pub/ipv6">
ftp://ftp.inner.net/pub/ipv6</a> (via IPv4).<P>
More information on using IPv6 with Linux can be obtained from:
<UL>
<LI>
<a href="http://www.bieringer.de/linux/IPv6/IPv6-HOWTO/IPv6-HOWTO.html">
http://www.bieringer.de/linux/IPv6/IPv6-HOWTO/IPv6-HOWTO.html</a>
<LI>
<a href="http://www.ipv6.inner.net/ipv6">http://www.ipv6.inner.net/ipv6</a>
(via IPv6)
<LI>
<a href="http://www.inner.net/ipv6">http://www.inner.net/ipv6</a> (via IPv4)
</UL>
<hr>
<h2><a name="R1">R1. Fetchmail's initial gethostbyname call fails on my host.</a></h2>
This is probably due to a DNS or NIS misconfiguration. The first
thing to do is check your /etc/hosts file for duplicate or missing
entries related to your host.<P>
<hr>
<h2><a name="R2">R2. Fetchmail isn't working, and -v shows `SMTP connect failed' messages.</a></h2>
Fetchmail itself is probably working, but your SMTP port 25 listener
is down or inaccessible.<p>
The first thing to check is if you can telnet to port 25 on your smtp
host (which is normally `localhost' unless you've specified an smtp
option in your .fetchmailrc or on the command line) and get a greeting
line from the listener. If the SMTP host is inaccessible or the listener
is down, fix that first.<p>
If the listener seems to be up when you test with telnet, the most
benign and typical problem is that the listener had a momentary seizure
due to resource exhaustion while fetchmail was polling it -- process
table full or some other problem that stopped the listener process
from forking. If your SMTP host is not `localhost' or something else
in /etc/hosts, the fetchmail glitch could also have been caused by
transient nameserver failure. <p>
Try running fetchmail -v again; if it succeeds, you had one of these
kinds of transient glitch. You can ignore these hiccups, because a
future fetchmail run will get the mail through. <p>
If the listener tests up, but you have chronic failures trying to
connect to it anyway, your problem is more serious. One way to work
around chronic SMTP connect problems is to use --mda. But this only
attacks the symptom; you may have a DNS or TCP routing problem. You
should really try to figure out what's going on underneath before it
bites you some other way. <p>
We have one report (from toby@eskimo.com) that you can sometimes solve
such problems by doing an <CODE>smtp</CODE> declaration with an IP
address that your routing table maps to something other than the
loopback device (he used ppp0).<p>
We also have a report that this error can be caused by having an
/etc/hosts file that associates your client host name with more than
one IP address.<P>
It's also possible that your DNS configuration isn't
looking at <code>/etc/hosts</code> at all. If you're using libc5,
look at <code>/etc/resolv.conf</code>; it should say something like
<pre>
order hosts,bind
</pre>
so your <code>/etc/hosts</code> file is checked first. If you're
running GNU libc6, check your <code>/etc/nsswitch</code> file. Make
sure it says something like
<pre>
order hosts,bind
</pre>
again, in order to make sure <code>/etc/hosts</code> is seen first.<P>
We had another report from a Linux user of fetchmail 2.1 who solved his SMTP
connection problem by removing the reference to -lresolv from his link
line and relinking. Apparently in some older Linux distributions the
libc bind library version works better.<p>
As of 2.2, the configure script has been hacked so the bind library is
linked only if it is actually needed. So under Linux it won't be, and
this particular cause should go away.<p>
<hr>
<h2><a name="R3">R3. When I try to configure an MDA, fetchmail doesn't work.</a></h2>
(I hear this one from people who have run into the blank-line problem in <a href="#X1">X1</a>.)<p>
Try sending yourself test mail and retrieving it using the
command-line options `<CODE>-k -m cat</CODE>'. This will dump exactly what
fetchmail retrieves to standard output (plus the Received line
fetchmail itself adds to the headers). <p>
If the dump doesn't match what shows up in your mailbox when you
configure an MDA, your MDA is mangling the message. If it doesn't
match what you sent, then fetchmail or something on the server is
broken.<p>
<hr>
<h2><a name="#R4">R4. Fetchmail dumps core when given an invalid rc file.</a></h2>
This is usually reported from AIX or Ultrix, but has even been known
to happen on Linuxes without a recent version of <code>flex</code>
installed. The problem appears to be a result of building with an
archaic version of lex.<P>
Workaround: fix the syntax of your .fetchmailrc file.<P>
Fix: build and install the latest version of <a
href="ftp://prep.ai.mit.edu/~ftp/pub/gnu">flex</a> from the Free
Software Foundation. An FSF <a
href="http://www.gnu.ai.mit.edu/order/ftp.html">mirror site</a>
will help you get it faster.<P>
<hr>
<h2><a name="R5">R5. Fetchmail dumps core in -V mode, but operates normally otherwise.</a></h2>
We've had this reported to us under Linux using libc-5.4.17 and gcc-2.7.2.
It does not occur with libc-5.3.12 or earlier versions.<p>
Workaround: link with GNU malloc rather than the stock C library malloc.<p>
We're told there is some problem with the malloc() code in that
version which makes it fragile in the presence of multiple free()
calls on the same pointer (the malloc arena gets corrupted).
Unfortunately it appears from doing gdb traces that whatever free()
calls producing the problem are being made by the C library itself, not the
fetchmail code (they're all from within fclose, and not an fclose called
by fetchmail, either).<p>
<hr>
<h2><a name="R6">R6. Fetchmail dumps core when I use a .netrc file but works otherwise.</a></h2>
We have a report that under Solaris 2.5 using gcc-2.7.2, if fetchmail
is compiled with -O or -O2, it segfaults on startup when reading a
.netrc.<p>
You can work around this by disabling optimization.<p>
There may be an actual bug here that the optimizer exposes; the stack
trace says the segfault is in free() and has all the earmarks of a heap-
corruption screw. But the symptom doesn't reproduce under Linux with the
same .fetchmailrc and .netrc.<p>
<hr>
<h2><a name="R7">R7. Running fetchmail in daemon mode doesn't work.</a><br></h2>
We have one report from a Solaris 4.1.4 user that trying to run
fetchmail in detached daemon mode doesn't work, but that using the
same options with -N (nodetach) is OK.<P>
If this happens, you have a specific portability problem with the code
in daemon.c that detaches and backgrounds the daemon fetchmail. Tell
me about it so I can try to fix it. As a workaround, you can start
fetchmail with -N and an ampersand to background it.<P>
This should not happen under Linux or any truly POSIX-conformant Unix.<P>
<hr>
<h2><a name="R8">R8. Fetchmail hangs when used with pppd.</a></h2>
Your problem may be with pppd's `demand' option. We have a report that
fetchmail doesn't play well with it, but works with pppd if `demand'
is turned off. We have no idea why this is.<p>
<hr>
<h2><a name="#R9">R9. Fetchmail randomly dies with socket errors.</a></h2>
Check the MTU value in your PPP interface reported by
<code>/sbin/ifconfig</code>. If it's over 600, change it in your PPP
options file. (<code>/etc/ppp/options</code> on my box). Here are
option values that work:<P>
<pre>
mtu 552
mru 552
</pre>
<hr>
<h2><a name="D1">D1. I think I've set up fetchmail correctly, but I'm not getting any mail.</a></h2>
Maybe you have a .forward or alias set up that you've forgotten about. You
should probably remove it.<p>
Or maybe you're trying to run fetchmail in multidrop mode as root
without a .fetchmailrc file. This doesn't do what you think it
should; see question <a href="#C1">C1</a>.<p>
Or you may not be connecting to the SMTP listener. Run fetchmail -v
and see <a href="#R1">R1</a>.<p>
<hr>
<h2><a name="D2">D2. All my mail seems to disappear after an interrupt.</a></h2>
One POP3 daemon used in the Berkeley Unix world that reports itself as
POP3 version 1.004 actually throws the queue away. 1.005 fixed that.
If you're running this one, upgrade immediately. (It also truncates
long lines at column 1024)<P>
Many POP servers, if an interruption occurs, will restore the whole
mail queue after about 10 minutes. Others will restore it right
away. If you have an interruption and don't see it right away, cross
your fingers and wait ten minutes before retrying.<P>
Some servers (such as Microsoft's NTMail) are mis-designed to restore
the entire queue, including messages you have deleted. If you have
one of these and it flakes out on you a lot, try setting a small
<code>--fetchlimit</code> value. This will result in more IP connects
to the server, but will mean it actually executes changes to the queue
more often.<P>
Qualcomm's qpopper, used at many BSD Unix sites, is better behaved.
If its connection is dropped, it will first execute all DELE commands (as
though you had issued a QUIT -- this is a technical violation of
the POP3 RFCs, but a good idea in a world of flaky phone lines). Then it
will re-queue any message that was being downloaded at hangup time.
Still, qpopper may require a noticeable amount of time to do deletions
and clean up its queue. (Fetchmail waits a bit before retrying in
order to avoid a `lock busy' error.)<P>
<hr>
<h2><a name="D3">D3. Mail that was being fetched when I interrupted my fetchmail seems to have been vanished.</a></h2>
Fetchmail only sends a delete mail request to the server when either
(a) it gets a positive delivery acknowledgement from the SMTP
listener, or (b) it gets an error 571 (the spam-filter error) from the
listener. No interrupt can cause it to lose mail.<p>
However, IMAP2bis has a design problem in that its normal fetch
command marks a message `seen' as soon as the fetch command to get it
is sent down. If for some reason the message isn't actually delivered
(you take a line hit during the download, or your port 25 listener
can't find enough free disk space, or you interrupt the delivery in
mid-message) that `seen' message can lurk invisibly in your server
mailbox forever.<p>
Workaround: add the `<CODE>fetchall</CODE>' keyword to your fetch options.<p>
Solution: switch to an <a href="http://www.imap.org">IMAP</a> server.<p>
<hr>
<h2><a name="M1">M1. I've declared local names, but all my multidrop
mail is going to root anyway.</a></h2>
Somehow your fetchmail is never matching the hostname part of
recipient names to the name of the mailserver machine. This probably
means it is unable to recognize hostname parts as being DNS names of
the mailserver, and indicates some kind of DNS configuration
problem either on the server or your client machine. <p>
The easiest workaround is to add a `<CODE>via</CODE>' option (if
necessary) and add enough aka declarations to cover all of your
mailserver's aliases, then say `<CODE>no dns</CODE>'. This will take
DNS out of the picture (though it means mail may be uncollected if
it's sent to an alias of the mailserver that you don't have
listed). <p>
It would be better to fix your DNS, however. DNS problems can hurt
you in lots of ways, for example by making your machines
intermittently or permanently unreachable to the rest of the net.<P>
<hr>
<h2><a name="M2">M2. I can't seem to get fetchmail to route to a local domain properly.</a></h2>
A lot of people want to use fetchmail as a poor man's internetwork
mail gateway, picking up mail accumulated for a whole domain in a single
server mailbox and then routing based on what's in the To/Cc/Bcc lines.<p>
In general, this is not really a good idea. It would be smarter to
just let the mail sit in the mailserver's queue and use fetchmail's
ETRN mode to trigger SMTP sends periodically (of course, this means
you have to poll more frequently than the mailserver's expiry period).
If you can't arrange this, try setting up a UUCP feed.<P>
If neither of these alternatives is available, multidrop mode may do
(though you <em>are</em> going to get hurt by some mailing list
software; see the caveats under THE USE AND ABUSE OF MULTIDROP
MAILBOXES on the man page). If you want to try it, the way to do it
is with the `<CODE>localdomains</CODE>' option.<p>
In general, if you use localdomains you need to make sure of two other
things: <p>
<strong>1. You've actually set up your .fetchmailrc entry to invoke multidrop mode.</strong><p>
Many people set a `<CODE>localdomains</CODE>' list and then forget
that fetchmail wants to see more than one name (or the wildcard `*')
in a `<CODE>here</CODE>' list before it will do multidrop routing.<p>
<strong>2. You may have to set `no envelope'.</strong><p>
Normally, multidrop mode tries to deduce an envelope address from a message
before parsing the To/Cc/Bcc lines (this enables it to avoid losing to mailing
list software that doesn't put a recipient addess in the To lines).<p>
Some ways of accumulating a whole domain's messages in a single server
mailbox mean it all ends up with a single envelope address that is
useless for rerouting purposes. You may have to set `<CODE>no
envelope</CODE>' to prevent fetchmail from being bamboozled by this.<p>
Check also answer <a href="#T1">T1</a> on a reliable way to do multidrop
delivery if your ISP (or your mail redirection provider) is using qmail.<p>
<hr>
<h2><a name="M3">M3. I tried to run a mailing list using multidrop, and I have a mail loop!</a></h2>
This isn't fetchmail's fault. Check your mailing list. If the list
expansion includes yourself or anybody else at your mailserver (that is, not on
the client side) you've created a mail loop. Just chop the host part off any
local addresses in the list.<p>
If you use sendmail, you can check the list expansion with
<CODE>sendmail -bv</CODE>.<p>
<hr>
<h2><a name="M4">M4. My multidrop fetchmail seems to be having DNS problems.</a></h2>
We have one report from a Linux user (not the same one as in <a
href="#R1">R1</a>!) who solved this problem by removing the reference
to -lresolv from his link line and relinking. Apparently in some
recent Linux distributions the libc bind library version works
better.<p>
As of 2.2, the configure script has been hacked so the bind library is linked
only if it is actually needed. So under Linux it won't be, and this problem
should go away.<p>
<hr>
<h2><a name="M5">M5. I'm seeing long DNS delays before each message is processed.</a></h2>
Use the `<CODE>aka</CODE>' option to pre-declare as many of your
mailserver's DNS names as you can. When an address's host part
matches an aka name, no DNS lookup needs to be done to check it.<p>
If you're sure you've pre-declared all of your mailserver's DNS dames,
you can use the `<CODE>no dns</CODE>' option to prevent other hostname
parts from being looked up at all.<p>
Sometimes delays are unavoidable. Some SMTP listeners try to call DNS
on the From-address hostname as a way of checking that the address is valid.<p>
<hr>
<h2><a name="M6">M6. How do I get multidrop mode to work with majordomo?</a></h2>
In order for sendmail to execute the command strings in the majordomo
alias file, it is necessary for sendmail to think that the mail it
receives via SMTP really is destined for a local user name. A normal
virtual-domain setup results in delivery to the default mailbox,
rather than expansion through majordomo.<P>
Michael <michael@bizsystems.com> gave us a recipe for dealing
with this case that pairs a run control file like this:<P>
<pre>
poll your.pop3.server proto pop3:
no envelope no dns
localdomains virtual.localdomain1.com virtual.localdomain2.com ...
user yourISPusername is root * here,
password yourISPpassword fetchall
</pre>
with a hack on your local sendmail.cf like this:<P>
<pre>
#############################################
# virtual info, local hack for ruleset 98 #
#############################################
# domains to treat as direct mapped local domain
CVvirtual.localdomain1.com virtual.localdomain2.com ...
---------------------------
in ruleset 98 add
-------------------------
# handle virtual users
R$+ <@ $=V . > $: $1 < @ $j . >
R< @ > $+ < @ $=V . > $: $1 < @ $j . >
R< @ > $+ $: $1
R< error : $- $+ > $* $#error $@ $1 $: $2
R< $+ > $+ < @ $+ > $: $>97 $1
</pre>
This ruleset just strips virtual domain names off the addresses of incoming
mail. Your sendmail must be 8.8 or newer for this to work. Michael
says:<P>
<BLOCKQUOTE>
I use this scheme with 2 virtual domains and the default ISP
user+domain and service about 30 mail accounts + majordomo on my
inside pop3 server with fetchmail and sendmail 8.83<P>
</BLOCKQUOTE>
<hr>
<h2><a name="X1">X1. Spurious blank lines are appearing in the headers of fetched mail.</a></h2>
What's probably happening is that the POP/IMAP daemon on your
mailserver is inserting a non-RFC822 header (like X-POP3-Rcpt:) and
something in your delivery path (most likely an old version of the
<em>deliver</em> program, which sendmail often calls to do local delivery) is
failing to recognize it as a header.<p>
This is not fetchmail's problem. The first thing to try is installing
a current version of <em>deliver</em>. If this doesn't work, try to
figure out which other program in your mail path is inserting the
blank line and replace that. If you can't do either of these things,
pick a different MDA (such as procmail) and declare it with the
`<CODE>mda</CODE>' option.<p>
<hr>
<h2><a name="X2">X2. My mail client can't see a Subject line.</a></h2>
First, see <a href="#X1">X1</a>. This is quite probably the same
problem (X-POP3-Rcpt header or something similar being inserted by
the server and choked on by an old version of <em>deliver</em>).<p>
The O'Reilly sendmail book does warn that IDA sendmail doesn't process
X- headers correctly. If this is your problem, all I can suggest is
replacing IDA sendmail, because it's broken and not RFC822 conformant.<p>
<hr>
<h2><a name="X3">X3. Messages containing "From" at start of line are being split.</a></h2>
If you know the messages aren't split in your server mailbox, then this
is a problem with your POP/IMAP server, your client-side SMTP listener or
your local delivery agent. Fetchmail cannot split messages.<p>
Some POP server daemons ignore Content-Length headers and split messages on
From lines. We have one report that the 2.1 version of the BSD popper
program (as distributed on Solaris 2.5 and elsewhere) is broken this way.<p>
You can test this. Declare an mda of `cat' and send yourself one
piece of mail containing "From" at start of a line. If you see a
split message, your POP/IMAP server is at fault. Upgrade to a more
recent version.<p>
Sendmail and other SMTP listeners don't split RFC822 messages either.
What's probably happening is either sendmail's local delivery agent or
your mail reader are not quite RFC822-conformant and are breaking
messages on what it thinks are Unix-style From headers. You can
figure out which by looking at your client-side mailbox with vi or
more. If the message is already split in your mailbox, your local
delivery agent is the problem. If it's not, your mailreader is the
problem.<p>
If you can't replace the offending program, take a look at your
sendmail.cf file. There will likely be a line something like<p>
<pre>
Mlocal, P=/usr/bin/procmail, F=lsDFMShP, S=10, R=20/40, A=procmail -Y -d $u
</pre>
describing your local delivery agent. Try inserting the `E' option in the
flags part (the F= string). This will make sendmail turn each dangerous
start-of-line From into a >From, preventing programs further downstream
from acting up.<p>
<hr>
<h2><a name="generic_mangling"><a name="X4">X4. My mail is being mangled in a new and different way</a></a></h2>
The first thing you need to do is pin down what program is doing the
mangling. We don't like getting bug reports about fetchmail that are
actually due to some other program's malfeasance, so please go through
this diagnostic sequence before sending us a complaint.<P>
There are five possible culprits to consider, listed here in the order
they pass your mail:<P>
<ol>
<li> Programs upstream of your server mailbox.
<li> The POP or IMAP server on your mailserver host.
<li> The fetchmail program itself.
<li> Your local sendmail.
<li> Your LDA (local delivery agent), as called by sendmail or
specified by <code>mda</CODE>.
</ol>
Often it happens that fetchmail itself is OK, but using it exposes
pre-existing bugs in your downstream software, or your downstream
software has a bad interaction with POP/IMAP. You need to pin down
exactly where the message is being garbled in order to deduce what is
actually going on.<P>
The first thing to do is send yourself a test message, and retrieve it
with a .fetchmailrc entry containing the following (or by running with
the equivalent command-line options):<P>
<pre>
mda "cat >MBOX" keep fetchall
</pre>
This will capture exactly what fetchmail gets from the server, except
for (a) the extra Received header line fetchmail prepends, (b) header address
changes due to <code>rewrite</code>, and (c) any changes due to the
<code>forcecr</code> and <code>stripcr</code> options. MBOX will in fact
contain what programs downstream of fetchmail see.<P>
The most common causes of mangling are bugs and misconfigurations in
those downstream programs. If MBOX looks unmangled, you will know
that is what is going on and that it is not fetchmail's problem. Take
a look at the other FAQ items in this section for possible clues about
how to fix your problem.<P>
If MBOX looks mangled, the next thing to do is compare it with your
actual server mailbox (if possible). That's why you specified
<code>keep</code>, so the server copy would not be deleted. If your
server mailbox looks mangled, programs upstream of your server mailbox
are at fault. Unfortunately there is probably little you can do about
this aside from complaining to your site postmaster, and nothing at
all fetchmail can do about it!<P>
More likely you'll find that the server copy looks OK. In that case
either the POP/IMAP server or fetchmail is doing the mangling. To
determine which, you'll need to telnet to the server port and simulate
a fetchmail session yourself. This is not actually hard (both POP3
and IMAP are simple, text-only, line-oriented protocols) but requires
some attention to detail. You should be able to use a fetchmail -v
log as a model for a session, but remember that the "*" in your LOGIN
or PASS command dump has to be replaced with your actual password.<P>
The objective of manually simulating fetchmail is so you can see
exactly what fetchmail sees. If you see a mangled message, then your
server is at fault, and you probably need to complain to your
mailserver administrators. However, we like to know what the broken
servers are so we can warn people away from them. So please send
us a transcript of the session including the mangling <em>and the
server's initial greeting line</em>. Please tell us anything else
you think might be useful about the server, like the server host's
operating system.<P>
If your manual fetchmail simulation shows an unmangled message,
congratulations. You've found an actual fetchmail bug. Complain
to us and we'll fix it. Please include the session transcript of
your manual fetchmail simulation along with the other things described
in the FAQ entry on <a href="#G3">reporting bugs</a>.
<hr>
<h2><a name="O1">O1. The --logfile option doesn't work if the logfile doesn't exist.</a></h2>
This is a feature, not a bug. It's in line with normal practice for
system daemons and allows you to suppress logging by removing the log,
without hacking potentially fragile startup scripts. To get around
it, just touch(1) the logfile before you run fetchmail (this will have
no effect on the contents of the logfile if it already exists).<P>
<hr>
<h2><a name="X5">X5. Using POP3, retrievals seems to be fetching too much!</a></h2>
This may happen in versions of fetchmail after 4.4.1 and before 4.4.8.
Versions after 4.4.1 use POP3's TOP command rather than RETR, in order
to avoid marking the message seen (leaving it unseen is helpful for
later recovery if you lose your connection in the middle of a
retrieval).<P>
Versions of fetchmail from 4.4.2 through 4.4.7 had a bad interaction
with Eudora qpopper versions 2.3 and later. The TOP bounds check was
fooled by an overflow condition in the TOP argument. Decrementing the
TOP argument in 4.4.7 fixed this.<P>
Fix: Upgrade to a later version of fetchmail.<P>
Workaround: set the <code>fetchall</code> option. Under POP3 in these
fetchmail version only, this had the side effect of forcing RETR
use.<P>
<hr>
<h2><a name="O2">O2. Every time I get a POP or IMAP message the header
is dumped to all my terminal sessions.</a></h2>
Fetchmail uses the local sendmail to perform final delivery, which
Netscape and other clients doesn't do; the announcement of new messages
is done by a daemon that sendmail pokes. There should be a ``biff''
command to control this. Type
<PRE>
biff n
</PRE>
to turn it off. If this doesn't work, try the command
<PRE>
chmod -x `tty`
</PRE>
which is essentially what <code>biff -n</code> will do. If this
doesn't work, comment out any reference to ``comsat'' in your
/etc/inetd.conf file and restart inetd.<P>
In Slackware Linux distributions, the last line in /etc/profile is
<PRE>
biff y
</PRE>
Change this to
<PRE>
biff n
</PRE>
to solve the problem system-wide.<P>
<hr>
<h2><a name="O3">O3. Does fetchmail reread its rc file every poll cycle?</a></h2>
No. Fetchmail only reads the rc file once, when it starts up. To
force an rc file reread, do <code>fetchmail -q; fetchmail</code>.<P>
<hr>
<h2><a name="O4">O4. Why do deleted messages show up again when I take
a line hit while downloading?</a></h2>
Because you're using a POP3 other than Qualcomm qpopper, or an IMAP
with a long expunge interval.<P>
According to the POP3 RFCs, deletes aren't actually performed until
you issue the end-of-session QUIT command. Fetchmail cannot fix this,
because doing it right takes cooperation from the server. There are
two possible remedies:<P>
One is to switch to qpopper (the free POP3 server from Qualcomm,
the Eudora people). The qpopper software violates the POP3 RFCs by
doing an expunge (removing deleted messages) on a line hangup, as well
as on processing a QUIT command.<P>
The other (which we recommend) is to switch to <a
href="http://www.imap.org">IMAP</a>. IMAP has an explicit expunge
command and fetchmail normally uses it to delete messages immediately
after they are downloaded.<P>
If you get very unlucky, you might take a line hit in the window
between the delete and the expunge. If you've set a longer expunge
interval, the window gets wider. This problem should correct itself
the next time you complete a successful query.<P>
<hr>
<h2><a name="O5">O5. Why is fetched mail being logged with my name, not the real From address?</a></h2>
Because logging is done based on the address indicated by the sending
SMTP's MAIL FROM, and some listeners are picky about that address.<p>
Some SMTP listeners get upset if you try to hand them a MAIL FROM
address naming a different host than the originating site for your
connection. This is a feature, not a bug -- it's supposed to help
prevent people from forging mail with a bogus origin site. (RFC 1123
says you shouldn't do this exclusion...)<p>
Since the originating site of a fetchmail delivery connection is
localhost, this effectively means these picky listeners will barf on
any MAIL FROM address fetchmail hands them with an @ in it!<p>
Versions 2.1 and up try the header From address first and fall back to
the calling-user ID. So if your SMTP listener isn't picky, the log
will look right.<p>
<hr>
<h2><a name="O6">O6. I'm seeing long sendmail delays at start of each poll cycle.</a></h2>
Sendmail does a hostname lookup when it first starts up, and also each
time it gets a HELO in listener mode.<p>
Your resolver configuration may be causing one of these lookups to
fail and time out. Check <code>/etc/resolv.conf</code> and
<code>/etc/hosts</code> file. Make sure your hostname and FQDN are
both in <code>/etc/hosts</code>, and that hosts is looked at before
DNS is queried. You probably also want your remote mail server(s) to
be in the hosts file.<p>
You can suppress the startup-time lookup if need to by reconfiguring
with <code>FEATURE(nodns)</code>.<p>
Configuring your bind library to cache DNS lookups locally may help,
and is a good idea for speeding up other services as well. Switching to
a faster MTA like qmail or exim might help. <p>
<hr>
<h2><a name="O7">O7. Why doesn't fetchmail deliver mail in date-sorted order?</a></h2>
Because that's not the order the server hands it to fetchmail in.<P>
Fetchmail getting mail from a POP server delivers mail in the order
that your server delivers mail. Fetchmail can't do anything about
this; it's a limitation of the underlying POP protocol.<P>
In theory it might be possible for fetchmail in IMAP mode to sort
messages by date, but this would be in violation of two basics of
fetchmail's design philosophy: (a) to be as simple and transparent a
pipe as possible, and (b) to <em>hide</em>, rather than emphasize, the
differences between the remote-fetch protocols it uses.<P>
Re-ordering messages is a user-agent function, anyway.<P>
<HR>
<table width="100%" cellpadding=0><tr>
<td width="30%">Back to <a href="index.html">Fetchmail Home Page</a>
<td width="30%" align=center>To <a href="/~esr/sitemap.html">Site Map</a>
<td width="30%" align=right>$Date: 1998/06/05 06:08:35 $
</table>
<P><ADDRESS>Eric S. Raymond <A HREF="mailto:esr@thyrsus.com"><esr@snark.thyrsus.com></A></ADDRESS>
</BODY>
</HTML>
|
