> In my setup here the mail sent to the mailing list bounces
>back to the list-owner even if there is one user wrong on the mailing
>list. No body on the mailing list seem to be receiving any mail when
>this happens. Once this user is removed from the mailing list things
>revert back to normal. This is kind of annoying......
It could be a sendmail bug.
I was just installing the following patch under SunOS 5.4, and
ran across the following bug/patch description:
>1153954 Unknown user in aliases kills an entire list
>Unknown user in aliases database prevents sendmail from
>delivering mail to other user on the same alias.
This is part of SunOS 5.4 sendmail patch 102066-04 (102066-01
being the patch above) The fix for CERT Advisory CA-95:05 on sendmail.
This may or not be relevant to your system, but it appears
that any sendmail based on Eric Allman's sendmail could have this
hope this helps.