Email Delivery Problems
 

Hi I have one huge headache I am running a Zimbra Mail server on Suse 10.3 which is behind a firewall/proxy. The firewall (also running suse) is set to redirect all request on ports 25 and 110 to my Mail server.

The Problem is this, some of the people trying to send mail to my domain get the following error - "smtp; 4.1.0 Unknown adress 450-'4.7.1 Client host rejected cannot find your hostname" .

Please any advice would be apreciated

"smtp; 4.1.0 Unknown adress 450-'4.7.1 Client host rejected cannot find your hostname"
Sounds to me like your server is verifying their mail servers identity by doing a rDNS lookup of the host name and comparing it to the MX records.

The problem is not on your end, but on their improperly configured mail servers usually due to incorrect or missing rDNS or MX records.

http://support.bluetie.com/node/402

Solved
 

That is what I thought and you were half right but in my case it turned that the dns server given to me by isp was crap so it only resolve some of the queries. All I did was add the correct Address into the resolv.conf file restart named and there we go everything works a treat.