Sendmail - Specify Interfaces
 

This is probably a simple question, but I just can't seem to find the answer.

I want to modify my sendmail configuration to utilize specific IP addresses for sending/receiving. I have multiple IP addresses bound to my network cards and watching the logs it seems to be using them at random. I want to make certain that if someone receives an email they are seeing a match of host name with IP address to try to avoid spam issues...

Try comment out the DAEMON_OPTIONS inputs below according to your own settings may help, but please check documentation for details.

Listening...
 

I am fairly confident that the above options line is related to which IP address the server is listening on. My issue is with the IP address that is being seen by the recipient's email server. Here is my situation...

My email server has multiple public IP addresses. Some of those addresses are in my DNS as servers being accessed from outside of our company. Some of the addresses would therefore be considered "dynamic" (though they are statically assigned).

When email is sent outbound thru sendmail, a remote mail system ends up seeing one of these IP addresses at random. A dynamic address is more likely to be flagged as "spammy" and thus I will start seeing rejections on email (this has happened).

My goal is to configure my server such that any outbound email will be seen by another server as coming from the same address - not one of my many at random...

As an interesting caveat to this, I need my users to be able to see a private IP address from within the company. I cannot configure it exclusively for a public address.