Sendmail 4 hour warning message
 

Hey everyone. I have 2 sendmail servers that are running in tandem to forward mail on to a smarthost. Lately (over the past couple of days) my mail queue has started to back up a little bit and users are getting messages about the mail being 4 hours old ("Warning: message still undelivered after 4 hours"). Is there a way to disable this message from being sent to them?

Yes, explicitly setting "Timeout.queuewarn.*" settings in sendmail.mc, generating sendmail.cf again and restarting Sendmail, but remember 0) these are sane defaults and 1) more importantly reconfiguring your MTA for what (hopefully) is a transient situation is a placebo: fix the cause, not the symptoms.

@unSpawn - I am of the same mindset. My boss, however, isn't. I believe that the issue resides with our hosted spam/virus filtering company that we smarthost the mail to but we're still looking into that. I really appreciate the info and the help on this. On a somewhat different note, I inherited this position as the Sendmail admin and haven't spent much time with the MTA before this (I was always an Exim guy). Do you have any suggestions on a comprehensive Sendmail guidebook?

O'Reilly's Bat book?