I believe a firewall is blocking some traffic that is preventing LISTSERV
from working properly.

The specific problem I have is this:
- The e-mail addresses that are being bounced are not being processed by
LISTSERV (when I look at my mail server logs, it shows that the bounced
e-mails are being denied access to my LISTSERV server). Therefore, no
e-mails are being deleted unless a subscriber explicitly states that they
want to be removed from the list.

Has anyone had any issues with this? Is this a firewall problem? Is it a
LISTSERV setting that I misconfigured?

Regards,
Ki Song