From OSSEC Wiki
Samples of a Postfix crash
Aug 27 12:07:46 kingston postfix/smtpd[13537]: connect from mail.netbsd.org[204.152.190.11]
Aug 27 12:07:47 kingston postfix/smtpd[13537]: warning: premature end-of-input on private/anvil while reading input attribute name
Aug 27 12:07:48 kingston postfix/smtpd[13537]: warning: connect to private/anvil: Connection refused
Aug 27 12:07:48 kingston postfix/smtpd[13537]: warning: problem talking to server private/anvil: Connection refused
Aug 27 12:07:48 kingston postfix/smtpd[13537]: warning: connect #1 to subsystem private/rewrite: Connection refused
Aug 27 12:07:58 kingston postfix/smtpd[13537]: warning: connect #2 to subsystem private/rewrite: Connection refused
Aug 27 12:08:08 kingston postfix/smtpd[13537]: warning: connect #3 to subsystem private/rewrite: Connection refused
Aug 27 12:08:18 kingston postfix/smtpd[13537]: warning: connect #4 to subsystem private/rewrite: Connection refused
Aug 27 12:08:28 kingston postfix/smtpd[13537]: warning: connect #5 to subsystem private/rewrite: Connection refused