I have a Centos64 new install as PDC. Postfix would receive but not send so following tips from Googling, I put a copy of the resolve config from /etc in /var/spool/postfix/etc and it stated delivering mail.

Then I started sorting out Samba and got that working (once I got it through the firewall) but it went at the speed of a plastic slug when trying to connect from windows boxes so I tried setting it to run wins.

At some point in this process the Postfix decided to stop resolving delivery host names again. So I checked all the settings and even set up Bind but the faults persist. I have a niggle they are related.

It doesn't help that the Postfix FAQ suggests looking at examples from the source man files but they don't exist with my install.

I can't post file contents at the moment as the building is closed for the nite and I am home with my laptop and piles of lost hair.

The Ppostfix SMTP delivery was caused by my putting the ADSL router IP in the resolve.cf for while it passes HTTP requests as a gateway, it fails at the level of MX records. I agreed with the advice found in many places in this forum about using dig to investigate rather than nslookup. What merit does nslookup have?