A letter like this is received by the email address who requested the subscription. As you can see below, the email address to be subscribed to the list will receive a confirmation letter much like this one.

Date: Fri, 9 Jun 2000 20:07:37 -0700 (MST) 
To: paul@Ag.Arizona.Edu 
From: majordomo@Ag.Arizona.Edu 
Subject: Majordomo results: subscribe list
Reply-To: majordomo@Ag.Arizona.Edu 


--


>>>> subscribe list
**** Your request to majordomo@ag.arizona.edu:
**** 
****    subscribe list gil@Ag.Arizona.Edu
**** 
**** must be authenticated.  To accomplish this, another request must be
**** sent in with an authorization key, which has been sent to:
****    gil@Ag.Arizona.Edu
**** 
**** If the message is not received, there is generally a problem with
**** the address.  Before reporting this as a problem, please note the
**** following:
****
**** You only need to give an address to the subscribe command if you want
**** to receive list mail at a different address from where you sent the
**** command.  Otherwise you can simply omit it.
****
**** If you do give an address to the subscribe command, it must be a legal
**** address.  It should not consist solely of your name.  The address must
**** point to a machine that is reachable from the list server.
****
**** If you have any questions about the policy of the list owner, please
**** contact "list-approval@ag.arizona.edu".
**** 
**** Thanks!
**** 
**** majordomo@ag.arizona.edu
>>>> end
END OF COMMANDS