See if there are any misconfigured MX hosts involved.  These can produce unpredictable results depending IF they get used in the delivery of email.

The way I read your email, s/he is doing forwarding from the old RFC822 address to a new one, further obfuscating delivery.

I suggest that the number of user initiated forward directives be eliminated and that the KISS approach be used.

Maybe a CHANGE would help?


/Pete


At 14:14 8/25/2006 Friday, Randy Klumph wrote:
>I have a subscriber who belongs to two lists on our server <tr.wou.edu>, a sub site of <wou.edu>
>
>Recently, I have been receiving the following error from both lists
>
>11 08/10 08/21 [log in to unmask]
>Last error: 5.1.1 550 5.1.1 unknown or illegal user: user@s21699
>
>The address in the subscriber lists for this person is <[log in to unmask]>
>
>If this weren't happening daily, I would assume it was just a spammer's spoofed address. Both lists are private.