Ok, so I've got a box named websrv1.mydomain.com. It's a web server running ubuntu, apache2, sendmail, etc.
My email is outsourced to a third party. So in my DNS I've got MX set to mx.thirdparty.net. I've no reason to accept incoming mail on my web server, every email should be sent to the third party. This works correctly accept with sending mail from the webserver (aka via cron or console).
So from my web server, if I send an email to firstname.lastname@example.org, it just disappears. No errors, nothing in dead.letter, nothing. I can send to any other address with no issues. If I send to email@example.com it's delivered locally which is fine.
1) Doing an nslookup shows the mx
record is correct.
2) Running /mx mydomain.com from sendmail -bt returns the correct result.
3) Running sendmail -bv firstname.lastname@example.org returns:
sudo sendmail -bv email@example.com firstname.lastname@example.org... deliverable: mailer esmtp, host mydomain.com., user email@example.com
4) Running 3,0 firstname.lastname@example.org, returns:
3,0 email@example.com canonify input: me @ mydomain . com Canonify2 input: me Canonify2 returns: me canonify returns: me parse input: me Parse0 input: me Parse0 returns: me Parse1 input: me MailerToTriple input: me MailerToTriple returns: me Parse1 returns: $# esmtp $@ mydomain . com . $: me parse returns: $# esmtp $@ mydomain . com . $: me
So I'm at a loss. Sendmail seems to see the mx record, but it's not using it.