Moderating an mlaliasThe moderator of an mlalias is the person designated to decide whether a given email should be forwarded to the mlalias or not. Emails sent to a moderated mlalias are checked to see if they originate from an authorised email address: if they do, they are sent straight to the list; if they don't, they are sent to the moderator for further action.
Make the list act as a moderated listEvery list is either unmoderated (the default), moderated, or members_can_post.
You need to set the list status flag to moderated if it is not so already. eg:
mlalias <list> -f moderated
Using the members_can_post flag instead will make the list moderated but also allow list subscribers to post to the list without moderation applying.
Setting the moderatorThe moderator must already be an owner of the mlalias, you can set both at once if need be:
mlalias <list> -A <moderator> -M <moderator>
Only one owner can act as moderator at a time, but you can change them around as needed. The moderator does not have to be a recipient (member) of the mlalias but does have to be a real person, not a NoLogin account. An exception is when permission to send to the list is handled entirely by netgroup membership, in which case the moderator is the dummy user udb. See cse-discussion for example.
Setting the authorised postersAuthorised posters are those accounts that can send email to the mlalias without requiring moderator approval. This includes:
- all owners of the mlalias
- any account explicitly set as an authorised poster, including members of netgroups
- all members of the mlalias IF the members_can_post flag is set
Passing and rejecting emails received by moderatorYou can recognise emails sent to you as moderator, rather than as a member of the list, by the fact that the following header is inserted into the email:
Received: For moderator-<list>@cse.unsw.edu.auwhere <list> is the name of the mlalias you moderate e.g. seminar-unsw. You may want to set your mail client to display this header, if possible, to make it easier to detect. If you decide the email is not suitable for the mailing list, you can then simply delete it or reply to the sender with an explanation. If the email is legitimate and suitably formatted for the mailing list the cleanest option is to bounce (also called redirect or forward without edit) the email to the mlalias. For both mutt and pine this is done by pressing 'b'. This resends the email to the members of the mlalias with the 'Received: For moderator' header stripped out but several ReSent- headers added for tracking purposes.
The reason bounce is preferable to forward is because it preserves the headers so the members of the mlalias will see the email as being sent by its originator rather than the moderator. However, some email clients don't support bounce so you may have to forward the emails and lose the sender information.
If the mlalias exists for a very restricted purpose, for instance forwarding bulletins from a particular site, it is easy to setup a procmail recipe to bounce these emails (since any email not from that site to the mlalias is automatically illegitimate) and the moderator can effectively forget about it.
When authorised posters overstep the boundsEmails sent by authorised posters do not, by definition, go to the moderator first. Hence if undesirable emails are sent to the list by such posters, the only action open to the moderator is to remove their authorised status. Being an owner of the mlalias the moderator can change the mlalias as they please, but it can be difficult to block one obstreperous member without affecting the others.
Read more about authorised posters.