unrouteable mail domain errors

[mickalo]

Hello,

we've all of sudden today notice that all outgoing emails sent from our server is getting the "unrouteable mail domain" error no matter what domain it is. nothing has been done with Exim and the exim_panic log shows no problems, just everything being sent out seems to generate this error.

what would cause this type of error ??

thx's
Mickalo

[Stefaans]

If Exim did not change and absolutely all email fails, then I think it can only be a DNS issue. I would start by checking that server resolves domains correctly:
* Check that /etc/resolv.conf references two or more valid name servers
* See what happens when you look up a domain, e.g. dig somedomain.com

I hope this helps