diff options
Diffstat (limited to 'fetchmail.man')
| -rw-r--r-- | fetchmail.man | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/fetchmail.man b/fetchmail.man index 795bf57d..d562788c 100644 --- a/fetchmail.man +++ b/fetchmail.man @@ -10,7 +10,7 @@ .\" Load www macros to process .URL requests, this requires groff: .mso www.tmac .\" -.TH fetchmail 1 2020-12-15 "fetchmail 6.4.15" "fetchmail reference manual" +.TH fetchmail 1 2021-01-30 "fetchmail 6.4.16" "fetchmail reference manual" .SH NAME fetchmail \- fetch mail from a POP, IMAP, ETRN, or ODMR-capable server @@ -2580,11 +2580,24 @@ poll mailhost.net with proto imap: Use the multiple-local-recipients feature with caution -- it can bite. All multidrop features are ineffective in ETRN and ODMR modes. -Also, note that in multidrop mode duplicate mails are suppressed. A -piece of mail is considered duplicate if it has the same message-ID as +Also, note that in multidrop mode duplicate mails may be suppressed. +A piece of mail is considered duplicate if it does not have a discernable +envelope recipient address, has the same header as the message immediately preceding and more than one addressee. Such runs of messages may be generated when copies of a message addressed -to multiple users are delivered to a multidrop box. +to multiple users are delivered to a multidrop box. (To be precise, +fetchmail 6.2.5 through 6.4.X use an MD5 hash of the raw message header, +and only fetchmail 6.4.16+ document this properly. +Fetchmail 5.0.8 (1999-09-14) through 6.2.4 used only the Message-ID header. +5.0.7 and older did not suppress duplicates.) + +Note that this duplication killer code checking the entire header is +very restrictive and may not suppress many duplicates in practice - for +instance, if some X-Original-To or Delivered-To header differs. This is +intentional and correct in such situations: wherever envelope information is +available, it should be used for reliable delivery of mailing list and blind +carbon copy (Bcc) messages. See the subsection Duplicate suppression below +for suggestions. .SS Header vs. Envelope addresses The fundamental problem is that by having your mailserver toss several @@ -2730,6 +2743,13 @@ this may change in a future version) you can declare 'no dns' to suppress DNS lookups entirely and \fIonly\fP match against the aka list. +.SS Duplicate suppression on multidrop +If fetchmail's duplicate suppression code does not kick in for your +multidrop mail account, other options is using sieve, or for instance +Courier's maildrop package (and in particular, its reformail program +with the -D option) as the delivery agent (either from fetchmail, +or from your local mail server that fetchmail injects into). + .SH SOCKS Support for socks4/5 is a \fBcompile time\fP configuration option. Once compiled in, fetchmail will always use the socks libraries and |