[Mailman-Users] Relay not permitted...

[Andrei]

Thanks to all of your suggestions I made some progress. Now, when I
try to send an email to test1 at lists.myhost.org I get an error message.

>From /var/log/exim4/mainlog

2009-09-01 17:39:02 H=mail-yx0-f203.google.com [209.85.210.203]
F=<myemail at gmail.com> rejected RCPT <test1 at lists.myhost.org>: relay
not permitted

In /etc/exim4/exim4.config there is this line
hostlist relay_from_hosts = MAIN_RELAY_NETS
but I don't know where to define "MAIN_RELAY_NETS"

Not sure if that's even the problem or not.