I just set up a mail server using http://library.linode.com/email/postfix.

I am able to log in to POP just fine and I'm able to send mail locally (using mailx), but I'm not able to send mail for an external address.

I don't receive any error messages, I don't see anything in the logs.

Could it be a DNS issue?
What other info would you need to help me debug?

It would be excellent if you could show us some of what /var/log/mail.log says as that would help us help you

This seems to be the relevant bit since the last restart. The pop3-logins are gmail:


Jun 4 10:51:07 li455-55 postfix/master[2098]: terminating on signal 15
Jun 4 10:51:07 li455-55 postfix/master[2678]: daemon started -- version 2.7.0, configuration /etc/postfix
Jun 4 10:56:02 li455-55 postfix/pickup[2680]: EA12C23692: uid=0 from=<root>
Jun 4 10:56:02 li455-55 postfix/cleanup[2693]: EA12C23692: message-id=<20120604155602.EA12C23692@li455-55.members.linode.com>
Jun 4 10:56:02 li455-55 postfix/qmgr[2681]: EA12C23692: from=<root@li455-55.members.linode.com>, size=388, nrcpt=1 (queue active)
Jun 4 10:56:03 li455-55 postfix/pipe[2697]: EA12C23692: to=<ryan@ohryan.ca>, relay=dovecot, delay=0.15, delays=0.1/0.01/0/0.04, dsn=2.0.0, status=sent (delivered via dovecot service)
Jun 4 10:56:03 li455-55 postfix/qmgr[2681]: EA12C23692: removed
Jun 4 11:32:09 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.140, lip=50.116.25.55, TLS
Jun 4 11:32:09 li455-55 dovecot: POP3(ryan@ohryan.ca): Connection closed top=0/0, retr=1/0, del=0/1, size=467
Jun 4 12:00:45 li455-55 postfix/pickup[2680]: 26E0023692: uid=0 from=<root>
Jun 4 12:00:45 li455-55 postfix/cleanup[2787]: 26E0023692: message-id=<20120604170045.26E0023692@li455-55.members.linode.com>
Jun 4 12:00:45 li455-55 postfix/qmgr[2681]: 26E0023692: from=<root@li455-55.members.linode.com>, size=372, nrcpt=1 (queue active)
Jun 4 12:00:45 li455-55 postfix/pipe[2791]: 26E0023692: to=<ryan@ohryan.ca>, relay=dovecot, delay=0.05, delays=0.03/0.01/0/0.01, dsn=2.0.0, status=sent (delivered via dovecot service)
Jun 4 12:00:45 li455-55 postfix/qmgr[2681]: 26E0023692: removed
Jun 4 12:02:14 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.139, lip=50.116.25.55, TLS
Jun 4 12:02:14 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=1/467, del=1/1, size=451
Jun 4 12:02:16 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.161, lip=50.116.25.55, TLS
Jun 4 12:02:16 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Jun 4 12:02:28 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.153, lip=50.116.25.55, TLS
Jun 4 12:02:28 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Jun 4 12:04:16 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.159, lip=50.116.25.55, TLS
Jun 4 12:04:16 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Jun 4 12:04:27 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.150, lip=50.116.25.55, TLS
Jun 4 12:04:27 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Jun 4 12:06:27 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.214.157, lip=50.116.25.55, TLS
Jun 4 12:06:27 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0
Jun 4 12:08:40 li455-55 dovecot: pop3-login: Login: user=<ryan@ohryan.ca>, method=PLAIN, rip=209.85.213.144, lip=50.116.25.55, TLS
Jun 4 12:08:40 li455-55 dovecot: POP3(ryan@ohryan.ca): Disconnected: Logged out top=0/0, retr=0/0, del=0/0, size=0

I'm guessing "ohryan.ca" is NOT hosted on your linode? or it is?

If not, you probably have it set somewhere to deliver EVERYTHING through dovecot. If it IS hosted on your linode (or postfix thinks it is) then postfix is doing everything correctly based on that log.

EDIT: I'm dumb, clearly it is hosted on your linode. From that log, everything is working as it should. Try to send an email to a domain not hosted on your linode and post that log section!

ohryan.ca is hosted on linode. The only messages that it has delivered are the ones I sent in ssh as root. There's no record of the messages I've been trying to send from external email addresses.

It seems your linode is not listening on port 25 (or there is a firewall in the way that is returning connection refused). That would be the problem.

Hm.

I haven't set up a firewall, iptables is not running.

Postfix appears to be listening to port 25.
root@li455-55:/etc/postfix# lsof -i tcp:25
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
master 3108 root 12u IPv4 8652 0t0 TCP localhost.localdomain:smtp (LISTEN)

Is it a problem that it's only listening to localhost.localdomain? If so where do I fix that?

It appears to be only listening on "localhost.localdomain" which is not generally publicly accessible. That is likely the issue. I cannot read it from my linode, that is for sure


telnet mail.ohryan.ca 25
Trying 50.116.25.55...
telnet: connect to address 50.116.25.55: Connection refused

Found it!

inet_interfaces was set to 'loopback-only' in main.cf. Changed it to 'all'.

Thanks for your help.

No problem. Glad it is working for you