If you have not already logged in, do so. If you have logged in and are not viewing the list dashboard, select List Dashboard from the List Management menu.
Locate the list you wish to modify in the list of your lists and select the Edit link in the Subscription column.
Now choose the option you'd like, By Owner or Closed.
Additionally, if you do not wish for the list to appear on the public list of LISTSERVs on this server, configure list security accordingly. Select the Configure link under the name of your list on the List Dashboard. Select the Security tab and set Confidential to YES.