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Why do messages have a different From: and CC: header?

By default, PennNet Mailing Lists remove all addresses from the TO: and CC: headers other than the list itself. For example, if a user sends a message such as:
When it is distributed to the subscribers of, those recipients only see the following:
This behavior can be changed to retain the contents of the TO: and CC: headers, but it is configured on a subscriber level basis, meaning that each individual subscriber may change their own personal setting. As as listowner, you may change the default setting which all subscribers receive when they are are subscribed. You must then also bulk change the setting for all existing subscribers.

The change the default setting for your list, add the following keyword to your list header:

Default-Options= IETFHDR
To change the settings for your existing subscribers, send the following command to
QUIET SET yourlistname IETFHDR FOR *@*
Note that setting IETFHDR for a list will supercede the setting of the Reply-To Keyword. When subscribers are set to IETFHDR, the Reply-To keyword will always be reset to Reply-To=Sender for those members.


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