[SOLVED] 450 4.7.25 Client host rejected: cannot find your hostname,

[killmasta93]

Hi,
I was wondering if someone could shed some light on the issue im having. Currnelty have disabled smtp helo checks, and greylist disabled and SPF disabled also. but i keep getting the

450 4.7.25 Client host rejected: cannot find your hostname,

any ideas?

Thank you

 

[IEM]

i find that sometimes postfix does not get restarted when changing things in the web-interface (the last thing i remember that failed to restart was when enabling/disabling SPF).

i usually resort to changing the smtp-banner as well, which
- seems to restart postfix
- allows me to do a simple check whether postfix was indeed restarted (if it shows the new banner, the restart was succesfull)

 

[tom]

Hi,
I was wondering if someone could shed some light on the issue im having. Currnelty have disabled smtp helo checks, and greylist disabled and SPF disabled also. but i keep getting the

450 4.7.25 Client host rejected: cannot find your hostname,

any ideas?

Thank you

Seems your public DNS entries are not set correctly?

 

[IEM]

Seems your public DNS entries are not set correctly?

i think the question is more targeted towards: "which checks must be disabled to accept connections from IPs with incorrect public DNS entries?"

 

[tom]

Please check your settings on "Configuration/Mail Proxy/Options: Reject Unknown Clients / Senders"

 

[killmasta93]

Thank you tom, that did the trick, i the difference from clients and senders would be?

 

[heutger]

Thank you tom, that did the trick, i the difference from clients and senders would be?

Unknown clients are hostnames not matching or existing (FCrDNS) of the sending mailserver, unknown senders checks, if the domain of the sender address exists.