[Mailman-Developers] No route to host problem

[Robby Griffin]

On Wednesday, Mar 17, 2004, at 16:10 US/Eastern, Kory Wheatley wrote:

> When I send a message to a mailman 2.1.4 mailing list using Postfix 
> from a yahoo account.   I receive an error message that says "No route 
> to Host".  It seems when I send out a message from our domain 
> "isu.edu" they are received, but from any other smtp host I receive 
> the below error:
>
> /var/log/maillog:Mar 17 01:55:24 lx5 postfix/smtp[16457]: 10F74124A31: 
> to=<wheakorypersonal at yahoo.com>, relay=none, delay=4956, 
> status=deferred (connect to mx4.mail.yahoo.com[216.155.197.63]: No 
> route to host)

The error itself is neither a postfix issue nor a mailman issue. "No 
route to host" means what it says. Check your routing and firewall 
configuration; your "lx5" machine needs to be allowed to establish 
connections to port 25 at arbitrary IP addresses in order to distribute 
mail. You may already have a well-defined set of outbound mail servers 
that are allowed to do this, in which case you should either configure 
mailman to use them, or add lx5 to the relevant firewall list. Outbound 
connections to port 25 may be blocked to slow the spread of email worms.

	--Robby