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I set up a server with Postfix/Dovecot on Linode/Ubuntu 10.04 according to this guide, admittedly I've never done this before. Local mail works just fine, but trying to send email to it from external addresses results in errors like this:

Delivery to the following recipient failed permanently:


Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 553 553 Unknown recipient. (state 13).

I honestly have no idea what to do or which configuration files/logs anyone needs to see.

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Is it a Linode server(I'm assuming) or EC2? If EC2, check the security group settings then confirm you setup your A records. – Publiccert Sep 26 '12 at 14:29
It is an Linode server. – Davis Sorenson Sep 26 '12 at 14:30
Confirm that your MTA is listening and then try and access the appropriate port externally. – Publiccert Sep 26 '12 at 14:38
(Took me some time to figure this out/test it on other servers) Postfix is listening for any ip4/6 address, when I do telnet smtp it gives me telnet: Unable to connect to remote host: Connection refused whereas servers not owned by me with working configuration give me: Trying <ip>... Connected to <fqdn>. Escape character is '^]'. and sometimes Connection closed by foreign host. at the end. I checked iptables and made a rule that explicitly accepts traffic on port 25, same results. – Davis Sorenson Sep 29 '12 at 12:36
check /var/log/mail.log and /var/log/mail.err – Laurentiu Roescu Nov 5 '12 at 16:09
up vote 1 down vote accepted

It turns out that I didn't have working DNS records.

I wanted mail to arrive at (Same server as, and be handled by that server. I made an A record for that had the server's ip, so the same ip as I then made the MX record for so that mail sent to would go to

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