Question Fail2ban with reverse DNS

[H.W.B]

Server operating system version

7.9.2009

Plesk version and microupdate number

18.0.44 Update #3

Hello,

A client is using a provider (starlinkisp.net).
Everytime he connect to the mailserver i got the following message :
Aug 9 22:49:08 plesk postfix/smtpd[21994]: warning: hostname <hostname> does not resolve to address <ipaddress>: Name or service not known
Aug 9 22:49:08 plesk postfix/smtpd[21994]: connect from unknown[<Ip address>]
And Fail2Ban Dovecot Jail bans this ip address.

Is there anything i can do to change this and that this will not resolve in a BAN without removing the Jail??

Thank you,

Henk

 

[IgorG]

warning: hostname <hostname> does not resolve to address <ipaddress>: Name or service not known

It seems the error refers to the fact that the hostname <hostname> cannot be resolved to <ipaddress>.
I would suggest resolving this matter first and seeing if that helps. For example, adding the hostname and IP to the /etc/hosts file so it can resolve at least locally. Or making sure the hostname resolves globally.
The similar issue described here: Unable to send or receive e-mail messages: Client host rejected: cannot find your hostname