hello guru's,

Here's a tough one for you...

I'm using sendmail as my MTA and all was well until one day it suddenly stopped.

I was using smart smtp to my ISP with access.db configured.
Here is the email that is bounced back each time an email is sent now:
Host unknown (Name server: .: host not found)
no name server? I can't figure it out I can nslookup everything in the world!

My /var/log/maillog sys this:
DSN: Host unknown (Name server: .: host not found)

If I do a /usr/lib/sendmail -v some@email.com < /etc/services

I get:
some@email.com... Connecting to [127.0.0.1] via relay...
220 localhost.localdomain ESMTP Sendmail 8.14.1/8.14.1; Tue, 27 May 2008 23:41:07 -0400
>>> EHLO localhost.localdomain
250-localhost.localdomain Hello localhost.localdomain [127.0.0.1], pleased to meet you
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-AUTH DIGEST-MD5 CRAM-MD5
250-DELIVERBY
250 HELP
>>> MAIL From:<me@localhost.localdomain> SIZE=381936 AUTH=me@localhost.localdomain
250 2.1.0 <me@localhost.localdomain>... Sender ok
>>> RCPT To:<some@email.com>
>>> DATA
250 2.1.5 <some@email.com>... Recipient ok
354 Enter mail, end with "." on a line by itself
>>> .
250 2.0.0 m4S3f7AJ003892 Message accepted for delivery
some@email.com... Sent (m4S3f7AJ003892 Message accepted for delivery)
Closing connection to [127.0.0.1]
>>> QUIT
221 2.0.0 localhost.localdomain closing connection


I was playing with my hostname a while back but as far as I know I revert all my changes....any ideas???

The remote MTA that is contacted to deliver or replay your e-mail has to be able to PTR your host. If it can't, and "localhost" isn't a routable or valid one, then it won't. If that's not it, please post *exact* loglines including the return codes.

Thanks for the reply unSpawn,

My ISP changed the FQ name of the SMTP server and while the old name was still forwarding to the new one, for some reason, sendmail requires the actual name. So once I changed it in the sendmail.mc and access did a quick make and restart sendmail everything is back to normal!