A little under a week ago, receipt of emails from external sources stopped working on the Fedora Core 4 system.
The error returned is:
TEMP_FAILURE: DNS Error: Timeout while contacting DNS servers

The DNS works - internet access for browsers etc still works.
Evolution works to retrieve emails from external POP3 servers.
Internal email (ie an email sent from the server machine) works, as does the aliasing (redirecting the mail to another address).

It is not just that no external email is able to be received by the system.

More information can be provided if necessary.

Any ideas?

Thanks in advance
Tony Sutherland

Have you done anything to sendmail or postfix (whichever you're using)?

Verify that you are not set for localhost only.

Thanks for the little piece of heads-up.
I have not (had not) changed anything in sendmail, but I will check nevertheless, and report back at first chance.