[wplug] Email bounce problem

[Bill Moran]

In response to Larry Daberko <larry at daberko.com>:

> Hi,
> 	I wanted to see if anyone else had this experience and could tell me 
> where to start looking.
> 
> 	I'm running a qmail server for my company and when a customer sends us 
> an email, sometimes it bounces back and they see:
> 
> > From: postmaster at hosting.com [mailto:postmaster at hosting.com]
> > Sent: Wednesday, June 14, 2006 11:28 AM
> > To: user at customer.com
> > Subject: Undeliverable Mail
> > 
> > Unknown user: info at mycompany.com
> > 
> > RCPT TO generated following response:
> > 550 <info at mycompany.com>... Relaying denied
> > 
> > Original message follows. 
> 
> What's throwing me off is the unknown user and relaying denied seems to 
> be two different error messages.  I've verified via logs that this 
> message never reached my server.  My server sends this format for 
> unknown users:
> 
> > Hi. This is the qmail-send program at mail.mycompany.com.
> > I'm afraid I wasn't able to deliver your message to the following addresses.
> > This is a permanent error; I've given up. Sorry it didn't work out.
> > 
> > <nobody at mycompany.com>:
> > Sorry, no mailbox here by that name. (#5.1.1)
> > 
> > --- Below this line is a copy of the message.
> 
> which is different that the one above.
> 
> I suspect that one of the hosting company's servers has a relay server 
> that's misconfigured.

Yup.  Do you have any backup MXes configured in DNS?  If so, you need to
ensure they all have updated mail address lists at all times.

It could also be on the user's end.  I've frequently had users complain
that they couldn't send me email, only to find that they couldn't send
email to _anyone_.

-- 
Bill Moran
Collaborative Fusion Inc.