Postfix connection lost after AUTH
- by user84104
Looking at the logs on my mailservers, I have noticed messages like the following:
Nov 29 12:09:38 mta postfix/smtpd[8362]: connect from unknown[183.13.165.14]
Nov 29 12:09:39 mta postfix/smtpd[8362]: lost connection after AUTH from unknown[183.13.165.14]
Nov 29 12:09:39 mta postfix/smtpd[8362]: disconnect from unknown[183.13.165.14]
Nov 29 12:09:39 mta postfix/smtpd[8409]: connect from unknown[183.13.165.14]
Nov 29 12:09:40 mta postfix/smtpd[8409]: lost connection after AUTH from unknown[183.13.165.14]
Nov 29 12:09:40 mta postfix/smtpd[8409]: disconnect from unknown[183.13.165.14]
There are no SASL failures in these cases. There are SASL failures are logged at other times, but never with lost connection after AUTH.
What is happening here, and should I do any about it?
These are not MXs, and already have smtpd_client_connection_rate_limit set.
Possibly related:
The systems require either SMTPS or STARTTLS before AUTH is announced.