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.
Maintainer feedback!
(In reply to Walter Schwarzenfeld from comment #1) This appears to have been a configuration issue. Functions correctly with ssmpt.conf of root=postmaster@ps1.hs mailhub=127.0.5.91:2525 Hostname=MYHOSTNAME UseTLS=YES rewriteDomain= #201910 added AuthUser=MYUSER AuthPass=MYPASSWD AuthMethod=LOGIN