@ Vance Yeah I believe it has to do with SMTP authentication. I went through ossec-list, but they just say do the tcp dump and check the archives.
So I went through Linode's document on setting up postfix for Gmail with my own domain, but I'm getting a "can't deliver mail" when doing the echo test. Link: https://www.linode.com/docs/email/postf ... tp-debian7
I tried the first two name servers just in case that was causing an issue, the email address is spelled right, and I setup an app specific password because I use two factor authentication.
The error in the email is: Note: I changed the domain name to example.
Final-Recipient: rfc822; firstname.lastname@example.org
Diagnostic-Code: X-Postfix; unknown user: "emailjim"