troubleshooting Question

Masquerading subdomains in sendmail

Avatar of brucepennypacker
brucepennypacker asked on
Email Servers
14 Comments1 Solution1282 ViewsLast Modified:
I have an environment where multiple servers are behind a firewall.  A few of these machines are completely inaccessable from outside the firewall, and hence they have names that are unresolvable on the internet.  I have them smarthosting through a machine that's publicly accessabe.  (These are centos linux machines by the way)  So, for example:

machine sits behind the firewall. machine is also behind the firewall but is publicly accessable.  There is forward/reverse DNS for but not for  On I have modified /etc/mail/ to contain define(`SMART_HOST', `'), and I've rebuilt and restarted sendmail.

When I try to send mail from it gets received by without any problems.  But then when tries to deliver the mail it usually gets rejected with a "Sender address rejected: Domain not found" error because the from address appears as

So what's the right way to configure sendmail to ensure these e-mails get delivered?  Having deliver the messages as just "" would be fine as far as I'm concerned.


Our community of experts have been thoroughly vetted for their expertise and industry experience.

Join our community to see this answer!
Unlock 1 Answer and 14 Comments.
Start Free Trial
Learn from the best

Network and collaborate with thousands of CTOs, CISOs, and IT Pros rooting for you and your success.

Andrew Hancock - VMware vExpert
See if this solution works for you by signing up for a 7 day free trial.
Unlock 1 Answer and 14 Comments.
Try for 7 days

”The time we save is the biggest benefit of E-E to our team. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.

-Mike Kapnisakis, Warner Bros