450 Client host rejected: cannot find your hostname

[jhoelz]

I need some help with this. While 95% or more of the mail rejected by this is spam, the other 5% is from domains we want to receive that are just not configured properly.

Is there a way to add domains to a list so they are not checked?

Global Settings as per attached image.

[mmorse]

Uncheck reject_unkonwn_client (else the senders have to have valid A & MX records).

I leave reject_unknown_client & reject_unknown_hostname off.
Once your sure that's the problem, try reject_unknown_sender_domain instead.

[randall]

Or another way to do it, since reject_unknown_client helps alot in countering spam, is to use the

check_client_access

in

postfix_recipient_restrictions.cf

and define those IP or domains or e-mail address that you would want to be accepted by your e-mail server.

But this should be place above those checking that you thick mark in your image attachment. Or before reject_unknown_client.

Hope this helps.