In message <AM9PR01MB8313FFDA84F12E9C138B699982152@AM9PR01MB8313.eurprd0 1.prod.exchangelabs.com>, Gellner, Oliver via mailop <mailop@mailop.org> writes
>As mentioned by Robert this is not coming from Google Workspace but Google >Groups. As far as I have understood it, spammers create or hijack newsgroups, >add countless addresses to the groups and then send their spam to the groups >addresses. > >To block Google Groups messages completely, you can filter for messages coming >from servers which resolve to *.google.com and contain the header "X-Google- >Group-Id". If you do not want or cannot wait until EOD you can check if MAIL >FROM includes "+bnc". However this might yield some false positives, as Google >users could use addresses which include this string. Some confusion here... Google Groups email comes from @googlegroups.com The other email containing "+bnc" is "Groups for Business" (the marketing name may differ from time to time...) which is like Google Groups except associated with a specific domain name (which you can find in the MAIL FROM) There are of course a great many legitimate Google Groups and legitimate Groups for Business. People can of course block what they wish... but you could well block some legitimate email by being too gung ho. Depending on your platform you should be able to block individual groups or individual GforB domains... Google Groups did have a big spam issue in that spammers could add anyone they wanted to the subscriber list ... they still can, but for the past few months no email will be sent until the new subscriber has responded to a "do you want to join" email. This is obviously an improvement but there are still many tens of thousands (I have $DAYJOB data to estimate from) of existing groups controlled by spammers. The Groups for Business system still allows for people to be added without confirmation, but does require the purchase of a domain for each spam run ... (assuming people complain) so it's not an unusually potent vector for spam sending. -- richard Richard Clayton Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. Benjamin Franklin 11 Nov 1755
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