Postfix: Host not found, try again

Posted on September 2, 2009

Small hint from me: If you set up Postfix to relay your mails and your relay host does not have an MX record (anymore), mailq has a lot of mails on standby and you see something like:

Jul 14 12:45:39 myhostname postfix/smtp[2349]: 74FBF30501:
        to=<recip@recip.domain> relay=none, delay=3944,
        status=deferred (Name service error for name=recip.domain
        type=MX: Host not found, try again)

And found this FAQ on Posfix.org and you say: “Yeah, the FAQ is right but so what now?”. Just boot your VI editor and open

editor /etc/postfix/main.cf

and change

relayhost = smtp.example.com:587

to

relayhost = [smtp.example.com]:587

and perform

/etc/init.d/posfitx reload

so Postfix will not looking for a valid MX record anymore. After this, go to the important work again…