The default setting for mail headers of incoming postings is SUBJecthdr for new lists. This setting causes the listname to appear as a subject tag on the subject line. For example,

Subject: [LISTNAME] This is your subject line

This setting also modifies the To: and Cc: headers so that only the listname address shows on the incoming To: header.

For example, if the message is sent with:


The message is received with:


Displaying full headers will show any other recipients in the Comments: header. If you want to receive messages so that the original To: and Cc: addresses are preserved, you can use the IETFhdr option. Note, however, that using the IETFhdr mail header option does not allow use of the subject tag and will ignore the Reply-To setting for the list.

To change the mail header option to IETFhdr via the web interface:

  1. Log In to LISTSERV.
  2. Click on Subscriber's Corner
  3. Select Settings for the list you wish to change from the List Names you are subscribed to.
  4. Update the option for Mail Header Style to sendmail-style [IETFhdr].

To change the mail header option to IETFhdr via e-mail:

  1. Address an e-mail message to
  2. Put the following in the body of the message:
    set listname IETFhdr
Article number: 
Last updated: 
September 17, 2021