DNS - Postfix

[Martin Hudec]

Hello Dave,


Dave Kingsley wrote:
> Our DNS server coughed a major hairball and our
> postfix based email setup suddenly stopped working.
> Here's our setup:
>    smtp server w/postfix also serving amavis w/sophie
>    imap server w/postfix mail store authentication via
> LDAP
> 
> Our problem seemd to be centered around MX records.?!
> 
> What do I need to post (file chuncks, etc.) to aid
> getting help?

First of all, if this issue seems to be related to MX, though you seem 
not to be sure, just use:

dig @server domain.tld -t mx

where server is the server(s) from /etc/resolv.conf and domain.tld is 
free to choose.

Nevertheless so far we do not have enough information to pinpoint the 
root cause. And as such we are just guessing.

Some questions that need to be answered:
1.) what exactly stopped to work? relaying, delivering, fetching?
2.) what say the logs?
3.) are there any firewalls on the way? if yes, were they reconfigured 
(as to stop either dns or mail traffic)?
5.) what is that hairball coughed by your dns?
4.) setup postfix to do debug, try to send mail and check logs? debug 
can be set by debug_peer_level (verbosity) and debug_peer_list (ip 
address for which verbosity will be increased).


Martin