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Topic: mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown

I am seeing a quite few of these messages, in the error log. Any ideas, how to troubleshoot this?

Feb 16 18:12:04 mail postfix/smtpd[13729]: connect from unknown[93.180.77.178]
Feb 16 18:12:50 mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown[93.180.77.178]
Feb 16 18:12:50 mail postfix/smtpd[13729]: disconnect from unknown[93.180.77.178]
Feb 16 18:13:31 mail postfix/smtpd[13729]: connect from unknown[93.180.77.178]
Feb 16 18:14:16 mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown[93.180.77.178]
Feb 16 18:14:16 mail postfix/smtpd[13729]: disconnect from unknown[93.180.77.178]
Feb 16 18:14:54 mail postfix/smtpd[13729]: connect from unknown[93.180.77.178]
Feb 16 18:15:40 mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown[93.180.77.178]
Feb 16 18:15:40 mail postfix/smtpd[13729]: disconnect from unknown[93.180.77.178]
Feb 16 18:16:21 mail postfix/smtpd[13729]: connect from unknown[93.180.77.178]
Feb 16 18:17:06 mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown[93.180.77.178]
Feb 16 18:17:06 mail postfix/smtpd[13729]: disconnect from unknown[93.180.77.178]

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Re: mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown

It should be OK.

This is caused by DNS resolve, because Postfix is chrooted under /var/spool/postfix/, it can't reverse IP address to hostname. Leave postfix 'smtpd' unchrooted in master.cf will fix it.

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Re: mail postfix/smtpd[13729]: too many errors after UNKNOWN from unknown

ZhangHuangbin wrote:

It should be OK.

This is caused by DNS resolve, because Postfix is chrooted under /var/spool/postfix/, it can't reverse IP address to hostname. Leave postfix 'smtpd' unchrooted in master.cf will fix it.

It should be ok, but because of this, with every email received Spamassassin triggers the RDNS_NONE rule with a score 1.274. That can make a difference for emails from being labelled as spam or not.