I feared that would be the case.
I would move anti-virus testing from clients to the mail server - at
least for outgoing mail and especially for those roaming users. Let them
switch off outbound mail checking by Norton Antivirus and on your
Sendmail mail server install clamav-milter to let it check for virus'.
Another good idea is to kick and ban such horrible software like OE.
There are much better 'free' alternates like Thunderbird.
Alexander
Thanks for all of your help and suggestion! My linux server has clamav
installed and it works well. However, some users still prefer their local
antivirus agent. Probably, that is the case and what I can do.
Hongwei