We have a cluster of RedHat Intel machines. One of these is a Dell
OptiFlex GX520; the others are HP/Compaq dc5000 MicroTowers, Dell OptiFlex
GX270 units, and a couple of other Intel boxes. We are in the process of
upgrading from FC4 to FC5.

The following problem has been occurring on some (but not all) of the
upgraded machines: mail sent to a local user is bouncing with a "550 User
unknown" error msg.

Some background:

(1) MX records have been set up so that dsm.dsm.fordham.edu is the mail
exchanger for dsm.fordham.edu.

(2) dsm.dsm.fordham.edu's mail-spool is NFS-mounted on all Linux hosts
in the dsm.fordham.edu domain.

The symptoms:

(1) If mail is sent to vader@dsm.fordham.edu from any of these machines,
then it goes through.

(2) If mail is sent to vader (as a local user) on *some* of the FC5
machines, root gets an email msg from mailer-daemon
procmail: Unknown user "vader"
550 5.1.1 ... User unknown

(3) Mail sent to vader (as a local user) on *some* of the FC5 machines and
*all* of the FC4 machines goes through. The "To:" header is not
"vader", but it's "vader@dsm.fordham.edu".

If anybody has an explanation for why sendmail is having this problem on
some (but not all) of our FC5 boxes, I would greatly appreciate knowing the
reason for the problem, as well as the solution.

Many thanks!!

Art Werschulz (8-{)} "Metaphors be with you." -- bumper sticker
GCS/M (GAT): d? -p+ c++ l u+(-) e--- m* s n+ h f g+ w+ t++ r- y?
Internet: agw STRUDEL cs.columbia.edu
ATTnet: Columbia U. (212) 939-7060, Fordham U. (212) 636-6325