Peter, > Jun 1 08:33:54 host postfix/smtpd[4431]: connect from > avk84-1-82-243-6-24.fbx.proxad.net[82.243.6.24] > Jun 1 08:33:54 host postfix/smtpd[4431]: lost connection after CONNECT > from avk84-1-82-243-6-24.fbx.proxad.net[82.243.6.24] > Jun 1 08:33:54 host postfix/smtpd[4431]: disconnect from > avk84-1-82-243-6-24.fbx.proxad.net[82.243.6.24] > > Why is it disconnecting so quickly? > > My onboard pf firewall is only showing occasional blocked ICMP (type 3, > code 1).
This is certainly one of the first things to fix. ICMP is not there just for fun and to be an 'ancilliary protocol', but has its function and purpose. ICMP type 3 must not be blocked by a firewall! Otherwise MSS negotiation does not work, which will cause seemingly unexplicable (some but not all) non-deliverable messages, and timeouts occur without client being able to report the reason for a failure. Type 4 can be useful, and type 11 makes outgoing traceroute work. Ping (0,8) can be useful. Other icmp types may be blocked, and some of them must be blocked (like redirects from outside). Mark _______________________________________________ AMaViS-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/amavis-user AMaViS-FAQ:http://www.amavis.org/amavis-faq.php3 AMaViS-HowTos:http://www.amavis.org/howto/
