Sender Header

Sympa follows Internet standards by transmitting messages with a Sender: 
header. This header indicates that the message was distributed to the mailing 
list by Sympa at the request of the original sender. The Sender: header 
follows the format of [listname]-request@utlists.utexas.edu.

MS Exchange will often treat the address in the Sender header as the original 
sender, which can cause that address to be cached in a user's outlook address 
list cache. This can lead to users sending messages to this '-request' address
which sends mail to the owners of the list, not the subscribers.

To avoid this potential confusion, ITS mail administrators will configure UT 
Austin Exchange to remove the Sender header from all inbound messages 
originating from UT Lists beginning on 5/26/2021. Recipients with mail addresses 
outside of the UT Austin Exchange environment will not be affected. This 
change will be transparent and exisiting mail filtering rules will not be 
impacted.

Outlook Address List Cache

Sometimes list messages to a small workgroup may not be received by the whole
group, because some are being inadvertently sent to the address
LISTNAME-request@utlists.utexas.edu. This "-request" address does not
distribute to the list, nor does it alert the sender that they made any kind of
mistake.

This address is intended to be used by people wanting to “request” something from
the list owners/moderators, so it is only sent to them and does not get sent to
the entire list.

For some users, the “request” address is getting cached in the Outlook
address list. When you open up a new window and start typing the list name, one
of the options that pops up as autocomplete results is that “request”
address, as shown here:

Outlook users can remove the -request list from the address cache by clicking
the "X" button next to the address.