Be careful with setting the timeout of sendmail to zero when trying to flush the mail queue:
sendmail -OTimeout.hoststatus=0m -q -v
Reason: a lot of target systems do rate-limiting if you retry too much in too short time, for instance gmail does that:
421-4.7.0 [###.###.###.### 15] Our system has detected an unusual rate of
421-4.7.0 unsolicited mail originating from your IP address. To protect our
421-4.7.0 users from spam, mail sent from your IP address has been temporarily
421-4.7.0 rate limited. Please visit
421-4.7.0 https://support.google.com/mail/answer/81126 to review our Bulk Email
421 4.7.0 Senders Guidelines. w1si28749381wju.16 - gsmtp
–jeroen
via Flush deferred messages in sendmail queue :: Stephan Paukner :: syslog.
Filed under: *nix, *nix-tools, Linux, openSuSE, Power User, SuSE Linux
