### 2.7.2 Sender filters

When a message is posted to the list, a series of moderation criteria are applied to determine the disposition of the message. This section contains the modeation controls for postings from both members and non-members.

default_member_moderation
  Member postings are held for moderation if their moderation flag is turned on. Note that only the list administrators can change the value of a member's moderation flag.

  You can control whether new members get their moderation flag turned on or off by default when they subscribe to the list. By turning this flag off by default, postings by members will be allowed without further intervention (barring other restrictions such as size or implicit recipient lists - see below). By turning the flag on, you can quarantine new member postings to make sure that they meet your criteria for netiquette, topicality, etc. Once you determine that the new member understands the community's posting rules, you can turn off their moderation flag and let their postings go through unstopped.

  E-newsletter style lists can also be set up by using the moderation flag. By setting the `member_moderation_action` to Reject, and by turning off the moderation flag for just the few approved senders, your list will operate in essentially a one-way direction. Note that you'd also need to reject or discard postings from non-members.

member_moderation_action
  This is the action to take for postings from a member who's moderation flag is set. For typical discussion lists, you'll likely set this to Hold so that the list moderator will get a chance to manually approve, reject, or discard the message. For e-newsletter and announcement lists, you might want to set this to Reject or Discard.

  Note that when a moderated member posts to your list, and the `member_moderation_action` is set to Hold, the message will appear on the administrative requests page. When you dispose of the message, you will be given an opportunity to clear the moderation flag at the same time. If you're quarantining new posts, this makes it very convenient to both approve a new member's post and de-moderate them at the same time.

member_moderation_notice
  When a member's moderation flag is turned on and `member_moderation_action` is Reject, this variable contains the text sent in the rejection notice.

The next batch of variables controls what happens when non-members post messages to the list. Each of these accepts one email address per line; regular expressions are allowed if the line starts with the (caret) character. These address lists are always consulted in the order in which they're presented on this page (i.e. accepts first, followed by holds, rejections, and discards).

accept_these_nonmembers
  Postings from non-members whose addresses match this list are accepted, barring other list restrictions due to size, implicit recipients, etc. You might want to add alternative addresses of approved posters to this list.

hold_these_nonmembers
  Postings from non-members whose addresses match this list are held for moderator approval.

reject_these_nonmembers
  Postings from non-members whose addresses match this list are rejected, i.e. bounced back to the original sender. There currently is no way to add additional text to the rejection message.

discard_these_nonmembers
  Postings from non-members whose addresses match this list are discarded, with no bounce back message. You might want to add the addresses of known spammers to this list.

generic_nonmember_action
  This variable controls what happens to non-member posts when the address of the sender doesn't match any of the above four lists. If you set this to Hold, the posting will appear on the administrative requests page, and you will be given an opportunity to add the non-member to one of the above four lists at the same time you dispose of the held message.

forward_auto_discards
  When messages from non-members are discarded, either because the sender address matched `discard_these_nonmembers`, or because `generic_nonmember_action` is Discard, you can choose whether such messages are forwarded to the lsit administrators or not.