Zitat von Tomas Macek <ma...@fortech.cz>:
I don't understand now, how Postfix behaves when listenting on submission port 587. Our mailserver is sometimes overloaded on port 25, so we want to use postscreen. But I don't understand, how Postfix works when it's stressed on port 587, when spammers connect to that opened port and want send their "emails". In document http://www.postfix.org/STRESS_README.html there is:NOTE: To avoid "overload" delays for end-user mail clients, enable the "submission" service entry in master.cf (present since Postfix 2.1), and tell users to connect to this instead of the public SMTP service.Should this mean, that Postfix by default does not use counters like smtpd_hard_error_limit, smtpd_junk_command_limit and maybe others on sumission port? On this port I would prefer using some kind of smtp auth and this port should be world accessible to allow the clients using other networks to authenticate and send emails.
Port 587 is by default nothing special for Postfix because it is mostly a clone of the Port 25 service. The *intended* difference is that Port 587 should only accept mail by authenticated users, so no chance for spammers if they don't own valid credentials. To actually see the difference between Port 25 and Port 587 settings you have to compare the entries in master.cf.
Regards Andreas
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