Bruce Hagen wrote:

To block a GMail domain, create a News Message Rule:

Where the from line contains people
Delete it and Stop processing more rules
Click on Contains People and Add the domain @gmail.com

There are a LOT more Gmail users than there are Google Grouping
spammers. While blocking on "googlegroups" in the Message-ID header
will get rid of a LOT of spam along with some Gmail users, my
perspective is that there is a lot of legitimate non-spamming Gmail
users posting through newsreaders to NNTP servers. Unfortunately,
Walter is using a newsreader that cannot test on the Message-ID header
and he probably doesn't want to bother setting up NewsProxy to do the
filtering for him.