How to setup a host as a sendmail relay for particular IP subnet

sendmail

By default, sendmail (I have version 8.13 on an RHEL4) allows only local mails.

I wanted to allow mails from a particular network to be relayed via the system, so I did the following based on suggestions from various places :

  1. /etc/mail/access : Added the subnet and the domain
    8.37 RELAY
    mydomain.com RELAY (I assume this is the originating email's domain)

This alone did not work, so I added the following to sendmail.mc
FEATURE(access_db)dbl

Now, the problem is that it is allowing access from other domains as well. To test it out, I removed 8.37 RELAY from the access, and changed the email from field to abhinav@notmydomain.org

However, I still receive the mail.

What is the correct way to configure this, so that only mails from a particular subnet are relayed ?

Best Answer

The correct syntax to allow a subnet to relay is:

Connect:192.168                 RELAY

How are you testing whether or not the server is disallowing relaying? Make sure that when you do your relay test, you're not trying to send mail to a domain hosted by the mail server. It'll accept it. Try using an external host to relay mail through your server to, say, gmail.

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