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I am following this guide on how to set up a mail server, Postfix, and one of the assumptions is that I should have an MX record for Postfix Guide However, I only have an MX record for, and when I try to DiG it, nothing appears.

I have set up everything, and it works, but it is a little bit alarming, I can telnet into localhost 25 and send an email from anybody with the command mail from:, and it gets sent without incident. It also displays the recipients as undisclosed recipients.

Do I need to somehow get an MX record for If so, how do I do that?

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The second paragraph is completely unrelated. It is also expected behavior; this is called an "open relay". Normally you'd require some kind of authentication for any external access, and possibly internal access. Most properly configured mail servers will mark your fake emails as spam, since they see that you're not the domain of the sender and you have nothing showing legitimacy. – Michael Lowman Feb 5 '12 at 18:50
Thanks, having never set up an email server, I was just posting behavior I wasn't expecting. – Cayetano Gonçalves Feb 5 '12 at 19:02
up vote 8 down vote accepted

You usually want to receive mail for, not for, so an MX entry for will be sufficient, which usually should point to to enable your mail server as an MX.

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Thank you, that clears up quite a bit of confusion then! – Cayetano Gonçalves Feb 5 '12 at 19:05

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