atom feed6 messages in net.sourceforge.lists.courier-usersRe: [courier-users] 456 plus 502 errors
FromSent OnAttachments
Mark ConstableApr 29, 2008 11:33 pm 
Bernd WurstApr 30, 2008 1:20 am 
Sam VarshavchikApr 30, 2008 4:01 am 
Mark ConstableApr 30, 2008 7:10 am 
Sam VarshavchikApr 30, 2008 3:25 pm 
Malcolm WeirApr 30, 2008 3:37 pm 
Subject:Re: [courier-users] 456 plus 502 errors
From:Sam Varshavchik (mrs@courier-mta.com)
Date:Apr 30, 2008 4:01:56 am
List:net.sourceforge.lists.courier-users

Mark Constable writes:

I need help with this one, if I try to send an email to anyone at @bigpond.net.au I get these 2 errors below but if I telnet to their MX hosts port 25 directly then a test message will go through okay so it seems to only be a problem when I send via my local courier-mta.

Apr 30 16:09:27 mail courieresmtpd: error,relay=::ffff:xx.240.81.28, from=<mar@renta.net>,to=<xy@bigpond.net.au>: 456 Address temporarily unavailable.

Apr 30 16:09:27 mail courieresmtpd: error, relay=::ffff:xx.240.81.28,msg="502 ESMTP command error",cmd: DATA

It's highly unlike that it's "anyone"@bigpond.net.au, but rather these specific recipients. Looking earlier in your mail log you should see a single delivery failure to these addresses, which starts the backscatter suppression timer.

This is backscatter suppression. You can read up on it in INSTALL and the courier man page.