> On Apr 25, 2016, at 1:02 PM, Steve Freegard <steve.freeg...@fsl.com> wrote: > > Hi all, > > We scan mail for a domain which uses Google Apps for Education and as part of > that they use Google Groups for communications to students. > > Does anyone have any idea why when someone sends a message to group > 'all_staff_and_stude...@domain.com' that Google insists on sending a single > message per-recipient from a host pool instead of sending a single message to > multiple groups of recipients (like 50-100 recipients or so)?
I'd assume it's so that they can handle bounces correctly, like all good mailing list software does. (Also to avoid the pain of trying to intuit what an after-DATA rejection or deferral means when there are multiple recipients). > Currently if someone sends a message with a 2Mb attachment we then see ~6Gb > of traffic back. It's made worse by the fact that if a user is on several > groups and those groups are members of other groups, they get the same > message 3 times (Google appears to discard the duplicates, we still receive > them though). It's like a big amplification attack for every message... > > Anyone have any ideas on how to tackle this? There's a bunch of user education the end user org could do but as a filtering-in-the-middle provider you're probably stuck with eating the bandwidth cost or inconveniencing your customer (by passing the cost on to them or putting size limits on mail you filter or ...) to encourage them to make changes, ideally changes you'd want them to make. Cheers, Steve _______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
