Unable to send and receive mails from some domains

[Bartimaeus]

Hi all,
I'm quite new to Zimbra and mail servers as a whole. We have set up zimbra mail server and we are able to send and receive email from and to almost everyone. The "almost" part is what we don't like currently. There is a domain that we cannot send emails to. It seems that their revers DNS is not configured properly. In the same time they have 2 MX records with different priorities (set correctly). However the one with the lower priority is the one that responds to our efforts to send emails.... which is odd.
Any ideas? Can we force Zimbra to send emails to a certain MX record?

[phoenix]

Originally Posted by Bartimaeus

Hi all,
I'm quite new to Zimbra and mail servers as a whole. We have set up zimbra mail server and we are able to send and receive email from and to almost everyone. The "almost" part is what we don't like currently. There is a domain that we cannot send emails to. It seems that their revers DNS is not configured properly.

Check the Admin UI and see what DNS & Protocol checks you have set and look in the log files to see exactly what error you're receiving.

[abacabb]

I think one possibility is that their mail server could be checking your setup against certain criteria they require....and rejecting mail as a result. Do you actually receive any rejection notifications from their server? Normally when email does not reach the destination you receive something back either from your server or their server telling you why.

I always like to run tools such as on dnsstuff.com and mxtoolbox.com to make sure my server meets industry standards.

Also.....check to see if you're blacklisted by anyone. I think its odd that you're able to send to some but not all.

[Bartimaeus]

Originally Posted by abacabb

I think one possibility is that their mail server could be checking your setup against certain criteria they require....and rejecting mail as a result. Do you actually receive any rejection notifications from their server? Normally when email does not reach the destination you receive something back either from your server or their server telling you why.

I always like to run tools such as on dnsstuff.com and mxtoolbox.com to make sure my server meets industry standards.

Also.....check to see if you're blacklisted by anyone. I think its odd that you're able to send to some but not all.

Actually I just checked the logs and I get:
host xxx.yyyy.zzz[aaa.bbb.ccc.ddd] said: 450 4.7.1 Client host rejected: cannot find your hostname, [aaa.bbb.ccc.ddd] (in reply to RCPT TO command)
After that my mail server tries the relay from the second MX record and goes to another server, which is not active at the moment.

[phoenix]

Originally Posted by Bartimaeus

Actually I just checked the logs and I get:
host xxx.yyyy.zzz[aaa.bbb.ccc.ddd] said: 450 4.7.1 Client host rejected: cannot find your hostname, [aaa.bbb.ccc.ddd] (in reply to RCPT TO command)
After that my mail server tries the relay from the second MX record and goes to another server, which is not active at the moment.

Then you need to fix the problem with your reverse DNS: +"4.7.1 Client host rejected: cannot find your hostname" - Yahoo! Search Results