On Thu, 24 May 2001 11:53:35 -0400, Michael Hensley <[log in to unmask]>
wrote:

>I received a complaint from a subscriber who had received 25 subscription
>probe [PROBE1] messages in the span of about 5 minutes.

Have you checked out the normal reasons for SMTP mail duplication in the
LISTSERV FAQ:  http://www.lsoft.com/manuals/lsv-faq.stm#5.6
and especially the known PIX Firewall mail duplication problem detailed in
http://www.lsoft.com/manuals/lsv-faq.stm#5.6a