Thanks for your reply!

Basically, here is my situation.

We already have an registered MX record for our Exchange server. No problems exist sending and receiving mails with the Exchange server.

Recently, we had to implement a UNIX server with support to our SAP application. When transactions are made with the SAP application, it sends out an e-mail confirmation to the client. This is all well and fine, except that some of our client's mail servers are rejecting e-mails coming from this UNIX server because it does not have a registered MX record on the internet. The solution that I've come up with is to route all the mails sending out from the UNIX server to our working Exchange server so that our client's mail server would accept the mails.

Here's a solution that I've found. But will this mask just the text level or the MX record level? If it's the MX record level, then I guess my problem is solved. Can someone confirm if this will solve my problem?

Thanks,

"Using the m4 macros, use:

MASQUERADE_AS(my.dom.ain)

This will cause all addresses to be sent out as being from the
indicated domain.

On your mailhub/mailhost/Domain Mail eXchanger, you may need to
add "my.dom.ain" to the sendmail.cw file or the "Cwhost.my.dom.ain"
line in the sendmail.cf file.

If you're using version 8.7 sendmail, and you want to hide this
information in the envelope as well as the headers, use:

FEATURE(masquerade_envelope)"