[Mailman-Users] Response: 450 Host down

Mark Sapiro mark at msapiro.net
Wed Dec 29 15:59:31 CET 2010

Joni Seth wrote:

>I have set up Mailman and Postfix, following the instructions to the letter, and although Mailman will send out email fine, when I, as the administrator, try to send my email to the list I have created, I get the following error: Response: 450 Host down (myserver.mydomain.org). I am quite new to this and am not a Mailman or Postfix expert by any means, but if someone could point me in the right direction, I would be very grateful. Thank you.

It is hard to say without more information, but it seems that the
server attempting to send your mail to the list is unable to establish
an SMTP connection to Postfix on the Mailman host.

Is there a DNS MX record for the list domain that points to the correct
host or if not, an A record that points to the correct host?

Is Postfix on the Mailman host listening on port 25? Do you get a
response from

  telnet myserver.mydomain.org 25

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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