For security and cost savings, you may want to configure a dial-up connection so that the server calls back your client computer. When you do this, the server-end incurs most of the telephone charges and stores the phone numbers of the computers with which it communicates.
This article assumes that a dial-up server is configured to allow dial-up users and that it is configured to use the callback feature. This article discusses the steps that an administrator needs to configure a Windows XP client to use the callback feature when dialing and connecting to a server.
To configure Windows XP to request a callback from a server:
Click Start, click Control Panel, and then click Network and Internet Connections.
In the Network and Internet Connections dialog box, click Network Connections.
Click Advanced, and then click Dial-up Preferences.
Click the Callback tab, and then choose the option that you want:
Ask me during dialing when the server offers.
Always call me back at the number below (select the modem that the server should call from the modem list, and click Edit to be sure you've entered the number of the phone line connected to the modem).
To use callback, Link Control Protocol (LCP) extensions must be enabled (they are enabled by default). This setting is controlled in the PPP Settings dialog box that you can access on the Networking tab of the connection properties dialog box.
The administrator of the server that you are dialing can change or override your callback privileges or callback settings. The server administrator can also deny callback, require callback to a particular phone number, or not allow callback options.