What is a callback system?

A.
It is a remote-access system whereby the remote-access server immediately calls the user back at
a predetermined number if the dial-in connection fails.

B.
It is a remote-access system whereby the user’s application automatically redials the remoteaccess
server if the initial connection attempt fails.

C.
It is a remote-access control whereby the user initially connects to the network systems via dial-up
access, only to have the initial connection terminated by the server, which then subsequently dials
the user back at a predetermined number stored in the server’s configuration database.

D.
It is a remote-access control whereby the user initially connects to the network systems via dial-up
access, only to have the initial connection terminated by the server, which then subsequently allows
the user to call back at an approved number for a limited period of time.

Explanation:
A callback system is a remote-access control whereby the user initially connects to the network
systems via dial-up access, only to have the initial connection terminated by the server, which then
subsequently dials the user back at a predetermined number stored in the server’s configuration
database.