Scott Techlist: > As I watch the bots and spammers hammer my server with connection attempts, > I figured I might as well stop them even closer to the front door when they > try repeatedly. > > I have fail2ban running already and once I enabled postscreen it didn't seem > to have much to do anymore. > > My primary question is: Can I filter on the DISCONNECT log line for bad > connections (and only bad connections), or do some "good" connections also > log a DISCONNECT.
Postcreen logs DISCONNECT for clients that PASS the "after 220 greeting" tests (bare newline, non-SMTP command, pipelining). I don't think there is much to gain from parsing postscreen logging to produce fail2ban rules. postscreen is designed to handle a lot of abuse with near-zero resources. Wietse