HELP - Mail bounceback issue

[chris4ops]

Hi all,

A client keeps getting this message from their SMTP:

########################################################

Reporting-MTA: dns;XXX.XXX.XXXX.XXX
Received-From-MTA: dns;KTES2292EVSS525.XXX.XX.XXXX.XXX
Arrival-Date: Thu, 7 Aug 2008 20:06:45 +0200

Final-Recipient: rfc822;xxxxx@yyyyyyyyy.com
Action: delayed
Status: 4.0.0
Diagnostic-Code: smtp;450 <xxx.xxxxx@xxx.xxxx.xxx>: Sender address rejected: Domain not found
Will-Retry-Until: Sat, 9 Aug 2008 20:06:45 +0200

###########################################################

Nobody from their domain can send it to anyone on our domain. Their thought is the problem is with our "digital signature" which i'm not sure how to change/modify. We use SunOS 5.8 and I believe we use Sendmail

Any help would be greatly appreciated.
Thanks

 

[Annihilannic]

I'd recommend posting this one in the sendmail forum, but it sounds to me like it is unable to resolve the domain name they are using in their email addresses?

Annihilannic.