Cathryn McGuire writes:
- Since this post in July, I've been trying to work with EMWD to get the cc's blocked.
It is unclear to me what you mean. If you want to prevent non-list addresses from appearing in the header of list posts as distributed, you can configure the list as anonymous (in which case it will appear to be From the list), or you could do something more complicated to remove those headers. See Mark's questions about "what do you want to happen when ..." in his parallel post. Note that BCCs never are seen by your host's mail server or by Mailman -- that is what the "blind" in "blind carbon copy" means.
If you want to prevent recipients of list posts from sending additional copies directly to personal addresses visible in the mail header, you're out of luck. You cannot block CCs or BCCs. They go directly from the person composing the message to the addressees. You could create a configuration where the list refuses to distribute messages with explicit addressees who are not the List Post or an Acceptable Alias, but those addressees would still get the CCs. And you can't do anything about BCCs, because your mailserver and Mailman never see those at all.
The only effective way to *prevent* these extra copies is to suspend or ban users who do it. The best way to handle it is to teach your subscribers to de-duplicate their email. Most mail clients have a feature to do this.[1] Some email providers will do this for you (I think Gmail does?)
Acceptable aliases
This is a list, one per line, of addresses and regexps matching addresses that are acceptable in To: or Cc: in lieu of the list posting address when 'require_explicit_destination' is enabled.
This means that these addresses satisfy the requirement that the list be explicitly addressed (no BCCs to the list). It does not mean that posts with addressees who are not the list will be rejected.
- Require Explicit Destination (this is a checked box. Could it be interfering with the Header filters?)
This means No BCCs To The List.
- Default action to take when a member posts to the list
Accept immediately (bypass other rules)
This is why your size filter has no effect.
Default Processing: run additional checks and accept the message. NOTE - when set here, all members are blocked.
You need to figure out why this is happening. See Mark's parallel post for some useful questions to diagnose it. Most important, check all the header filters.
Footnotes: [1] The usual implementation is to delete or suppress later messages with the same Message-ID. Unfortunately, the first to arrive is usually the CC or BCC copy, which lacks the list's "decorations" on distributed posts. A few subscribers are sensitive to this inconsistency, and they'll have to make a choice. I recommend that list owners should not use this feature if the list copy will be deleted.
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan