Eric,
 
I've installed LISTSERV Version 1.5h and I've got immediately a bunch of
rejected mail (I enclose below an example).
Now LISTSERV is stopped to avoid the problem.
The rejected mail files arrived here directly from the ARPA-Internet,
because our net is connected to it (via SATNET).
Our IBM 3081 runs the WISCNET software from Wisconsin University, and the
mail files were delivered to LISTSERV by the SMTPSERV virtual machine.
Could you help me to fix the problem?
 
Thanks in advance,
                  Laura