My brain must have been fried last night. I just noticed that I answered the question about callback, not callin authentication. Sorry if this caused any confusion. I'm giving up answering questions at 2:30 in the morning.
The actuall answer to the callin question is as follows: Callin is configured on the receiving device. Typically you will find this used in ISDN backup scenarios. There's a hub device that remote devices connect into for ISDN backup. Callin would be used on the hub device to authenticate icoming calls from the remote devices. By using callin, authentication only occurs on the hub device and not on the remote devices. I hope this helps. Carl Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=48440&t=48325 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]

