I'm not really sure if this is a bug, as I imagine it is by design, but since it sometimes works I thought I should report it and see if you have a solution that will work for me.
A couple of days ago we changed T1 lines from SBC to AT&T, on SBC we could send outgoing mail for one of our domains by using SBC's business outgoing mail server relay. With the new AT&T they are telling me they no longer offer this service.
So I tried sending mail out my virtualmin server for this domain that is NOT hosted by my virtualmin server, and I didn't think it would work, because that is considered mail relaying right? Anyways it did work, I double checked, and it allowed me to relay mail. I thought, maybe it was because I am in the same subnet or something. Anyways, now when I try to send the mail it fails (as I thought it should). It seems to work a small percentage of the time but of course this would not be reliable.
Have I somehow opened up my server as a mail relay?
How can I allow my local network to send mail from my virtualmin server for a domain that it does not host? I would rather use my virtualmin server to send outgoing mail for this non hosted domain then my ISP's outgoing mail server anyways, since its much faster, but this is corporate mail and the domain is hosted elsewhere. For some reason company poilcy states we must use our ISP to send outgoing mail.
I have two lan cards in this machine, so maybe I could tell it to allow mail relay from the local lan card and of course not from the other one. Although I dont think I have ever made any changes that should have allowed any mail to be sent from a non hosted domain, so I dont understand why it would have allowed any to be sent.
thanks