[CentOS] postfix and mail origin checks

Karanbir Singh wrote:
> hi,
> 
> Whats the 'robust' way to make sure email to a specific destination is 
> only accepted if it came over the localhost:25 or /usr/sbin/sendmail 
> route ? anything else should get a 5xx error. Emails to other 
> destinations should remain unaffected.
> 
> Using postfix/c4. Had a look around, and header_checks might be one way 
> to go.
> 

The easiest way is probably to edit master.cf and make smtpd only listen on localhost:25.


So instead of

# smtp      inet  n       -       n       -       -       smtpd

Use

127.0.0.1:smtp  inet    n       -       n       -       -       smtpd


Otherwise us an access table.


Glenn