### 2.1.2 Reply-To header munging

This section controls what happens to the Reply-To: headers of messages posted through your list.

Beware! Reply-To: munging is considered a religious issue and the policies you set here can ignite some of the most heated off-topic flame wars on your mailing lists. We'll try to stay as agnostic as possible, but our biases may still peak through.

Reply-To: is a header that is commonly used to redirect replies to messages. Exactly what happens when your users reply to such a message depends on the mail readers your users use, and what functions they provide. Usually, there is both a ``reply to sender'' button and a ``reply to all'' button. If people use these buttons correctly, you will probably never need to munge Reply-To:, so the default values should be fine.

Since an informed decision is always best, here are links to two articles that discuss the opposing viewpoints in great detail:

- Reply-To Munging Considered Harmful
- Reply-To Munging Considered Useful

The three options in this section work together to provide enough flexibility to do whatever Reply-To: munging you might (misguidingly :) feel you need to do.

first_strip_reply_to
  This variable controls whether any Reply-To: header already present in the posted message should get removed before any other munging occurs. Stripping this header will be done regardless of whether or not Mailman will add its own Reply-To: header to the message.

  If this option is set to No, then any existing Reply-To: header will be retained in the posted message. If Mailman adds its own header, it will contain addresses which are the union of the original header and the Mailman added addresses. The mail standards specify that a message may only have one Reply-To: header, but that that header may contain multiple addresses.

reply_goes_to_list
  This variable controls whether Mailman will add its own Reply-To: header, and if so, what the value of that header will be (not counting original header stripping - see above).

  When you set this variable to Poster, no additional Reply-To: header will be added by Mailman. This setting is strongly recommended.

  When you set this variable to This list, a Reply-To: header pointing back to your list's posting address will be added.

  When you set this variable to Explicit address, the value of the variable `reply_to_address` (see below) will be added. Note that this is one situation where Reply-To: munging may have a legitimate purpose. Say you have two lists at your site, an announce list and a discussion list. The announce list might allow postings only from a small number of approved users; the general list membership probably can't post to this list. But you want to allow comments on announcements to be posted to the general discussion list by any list member. In this case, you can set the Reply-To: header for the announce list to point to the discussion list's posting address.

reply_to_address
  This is the address that will be added in the Reply-To: header if `reply_goes_to_list` is set to Explicit address.