Bug 231046 - mail/ssmtp 2.64 doesnt send final ack - delays mail server with hanging LAST_ACT on FreeBSD11.2S
Summary: mail/ssmtp 2.64 doesnt send final ack - delays mail server with hanging LAST_...
Status: New
Alias: None
Product: Ports & Packages
Classification: Unclassified
Component: Individual Port(s) (show other bugs)
Version: Latest
Hardware: Any Any
: --- Affects Only Me
Assignee: freebsd-ports-bugs mailing list
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-08-31 03:21 UTC by dewayne
Modified: 2019-08-15 04:52 UTC (History)
2 users (show)

See Also:
bugzilla: maintainer-feedback? (aragon)


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Description dewayne 2018-08-31 03:21:36 UTC
Unsure if this is an implementation issue or something around traffic flow.

situation:
Multiple messages being sent with ssmtp.  When the server starts rejecting messages due to connection rate setting, there are pending LAST_ACKs; which ssmtp should ack before terminating.  Instead ssmtp just stops.

Resulting in sockstat -s revealing
root     sendmail   31777 5  tcp4   127.0.5.91:2525       127.0.5.91:41596      ESTABLISHED
root     sendmail   31777 11 tcp4   127.0.5.91:2525       127.0.5.91:41596      ESTABLISHED
root     ssmtp      31603 3  tcp4   127.0.5.91:36347      127.0.5.91:2525       ESTABLISHED
root     ssmtp      31381 3  tcp4   127.0.5.91:58319      127.0.5.91:2525       ESTABLISHED
root     ssmtp      31257 3  tcp4   127.0.5.91:41596      127.0.5.91:2525       ESTABLISHED
root     sendmail   39991 9  tcp4   127.0.5.91:2525       *:*                   LISTEN
?        ?          ?     ?  tcp4   127.0.5.91:2525       127.0.5.91:31082      LAST_ACK
?        ?          ?     ?  tcp4   127.0.5.91:2525       127.0.5.91:55470      LAST_ACK
?        ?          ?     ?  tcp4   127.0.5.91:2525       127.0.5.91:28956      LAST_ACK

The problem is that sendmail wont respond to new connections until the LAST_ACK timeouts.  

Workaround - increase number of connections to that particular port 2525 which is only for administrative email.  Aside: there are multiple jails transmitting to the sendmail (latest version) jail via lo0.  It just appears to be coming over its "localhost" addr.
Comment 1 Walter Schwarzenfeld freebsd_triage 2019-08-15 04:52:49 UTC
Maintainer feedback!