troubleshooting Question

Masquerading subdomains in sendmail

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brucepennypacker asked on
Email Servers
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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 hidden.foo.com sits behind the firewall. machine www.foo.com is also behind the firewall but is publicly accessable.  There is forward/reverse DNS for www.foo.com but not for hidden.foo.com.  On hidden.foo.com I have modified /etc/mail/sendmail.mc to contain define(`SMART_HOST', `www.foo.com'), and I've rebuilt sendmail.cf and restarted sendmail.

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

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

ASKER CERTIFIED SOLUTION
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