Sendmail Problem

[roobala]

Hi,

We are an ISP setup running sendmail version 8.8.6 and 8.11,
For the last 10 hrs, while trying to sendmail to the local domain, sendmail gives the following error,

"Deferred : Nameserver : -----
Hostname Lookup Failure"

This is not happening while sending mails to outside domains.

Can someone give suggestion for this problem.

Thanks and Regards.

[David Rodman]

This is almost certainly a name lookup issue. Try running
nslookup on the mx records not just the a records,
Your problem may be a misconfiguaration of the local domain.

Also look at /etc/nsswitch.conf and make sure the hosts options are what you want them to be.

[Tracey]

Make sure your /etc/hosts file has the line:

127.0.0.1 locahost loopback

Also that the /etc/hosts files has only one line for your host machine.