Wrong body with wrong headers!!! ?

[Tim Tyler]

Mailscanner experts,
   I have a situation I have never seen before.  I am running sendmail
8.9.3 in conjunction with mailscanner and sophos which I just intalled less
than a month ago to try out.  A user sent a message that became queued for
one reason or another.  The next day, another message came into the system
and took the same id number as the one that was queued (which I thought was
impossible).  The body of the message of the original sender was then sent
via the new headers to the new address.  I have no idea what happened to
the new body (perhaps simply lost).   Hence, a message was delivered to the
wrong destination because the process ID's cycled around in less than 24
hours.    How is this possible?  Is this the fault of sendmail or
mailscanner or AIX?  What might I do to prevent an identification number
from cycling around and being taken again by chance?  Is this a failure to
lock the queued files?
     Tim

Tim Tyler
Network Engineer - Beloit College
tyler at beloit.edu