Once upon a time, spammers sent messages to hundreds, even thousands of
recipients with the same sender address on each message. In that environment,
blocking messages from the sender address used by the spammer was an effective
way to block spam, and X-SPAM jobs enabled LISTSERV backbone servers to share
information about known spammers.

Spammer tactics have changed. Some spamware programs still send messages
with multiple recipients per message; other send individual messages to
individual recipients. In either case, the sender addresses on different
messages are likely to be different. Even without the phenomenal increase
in the volume of spam, this change in tactics would have resulted in a
significant increase in the number of X-SPAM jobs.

In the current environment, X-SPAM jobs now account for a significant
percentage of incoming mail, to the point that legitimate list postings
and command messages from legitimate users are often queued behind large
numbers of X-SPAM jobs. This is a self-inflicted denial of service.

I believe it is time for L-Soft to rethink its philosophy regarding
inter-server spam notifications. Perhaps X-SPAM updates should be sent
as periodic batch jobs to mitigate their impact on the receiving servers.
Perhaps X-SPAM updates should be an optional service to which individual
site administrators could subscribe. Perhaps there are other alternatives
that would allow backbone servers to continue to share spammer information
without impacting the services those servers were designed to provide.

--
Paul Russell
Senior Systems Administrator
OIT Messaging Services Team
University of Notre Dame