On Mon, Aug 27, 2018 at 2:50 AM Mark Sapiro <mark@msapiro.net> wrote:
That is not the issue. Sending the held message notice to a spammer, if it reaches the spammer, is probably inconsequential. The issue is that virtually always in spam the sender address is either undeliverable or is the address of an innocent 3rd party. Sending these notices to innocent 3rd parties is called backscatter and is a bad thing.
To avoid this backscatter, you can set the list's respond_to_post_requests attribute to False. There are two problems here. One is this setting is not currently exposed in Postorius, and the other is this will also stop desired held message notices such as those from list members.
Aha. That was a simple solution although with a bad consequence. Will it stop moderation mails to the moderator as well? I'll try. Otherwise it will not be a problem in my case. The lists where I have this problem are more of function addresses for a number of persons (like a board or workgroup) so they accept posts from non-members. I use mailman as a simple forward gets legit mail caught in the receivers spam filters and might cause more black-list problems.
You are of course entirely correct in that backscatter is the real problem, I should have thought of that. The thing in the spam I've received lately is somewhat sophisticated: the senders have correct (albeit strange) domains and correct SPF records so they try to seem legit although the senders are located in unexpected parts of the world. I just checked one example, in that case the MX pointed to the sender IP, the SPF was very sloppy (~all) and everything looked correct except for the fact that we usually do not receive mail from Ukraine and the cryptocurrency scam in the body. It almost got caught in the spam filter, but not quite.
cheers // David