IBM SC30-3681-08 manual Conguring PPP Callback, 459

Using PPP

Attention: Do not use the following commands unless you want the device to
	perform authentication as described in ªUsing Local or Remote
	Authenticationº in Using and Con®guring Features.
v	enable pap
v	enable chap
v	enable spap
	Note: SPAP is only available on interfaces that have IBM DIALs Dial-In circuits
	con®gured.
v	enable mschap

Con®guring PPP Callback

Callback is a PPP feature associated with single user dial-in solutions. It attempts to accomplish two objectives. These objectives are:

vCallback can be used as a form of security. When used in this way, callback is generally referred to as required callback. When required callback is negotiated the user will be dialed back at a predetermined number. Only then will the PPP link be allowed to come up.

vCallback can also be implemented as a toll-saver feature. When used in this way, callback is generally referred to as roaming callback. Unlike required callback, roaming callback is requested by the client. The primary function of roaming callback is to bill the company maintaining the DIALs Server the toll charges instead of the user.

Callback is supported only on dial-in dial circuits over V.34 or ISDN networks.
Example 1: Required callback enabled
Config>add PPP
Enter user name: [ ]? nocallback
Password:
Enter password again:
Is this a Single-User or a Network? (Single-User, Network): [Single-User]
IP address for user nocallback [0.0.0.0]?
Enter HostName: [ ]?
Give ©nocallback© default time allotted ? (Yes, No): [Yes]
Enable Callback for ©nocallback© ? (Yes, No): [No] yes
Type of Callback (Roaming Callback, Required Callback): [Roaming Callback] Requ
Dialback number for this user [ ]? 555-1234
Will ©nocallback© be able to dial-out ? (Yes, No): [No]
PPP User Name: nocallback
Type: Single User
User IP Address: Interface Default
SubNetMask: 255.255.255.255
Hostname: <undefined>
Time-Alotted: Box Default
Call-Back Type: Required Callback
Phone Number: 543-3186
Dial-Out: Not Enabled
Encryption: Not Enabled
Is information correct? (Yes, No, Quit): [No] yes
Example 2: Callback disabled
Config>add PPP
Enter user name: [ ]? sallydoe
Password:
Enter password again:
Is this a Single-User or a Network? (Single-User, Network): [Single-User]
IP address for user nocallback [0.0.0.0]?
Enter HostName: [ ]?
Give ©no callback© default time allotted ? (Yes, No): [Yes]
Enable Callback for ©no callback© ? (Yes, No): [No]
Will ©no callback© be able to dial-out ? (Yes, No): [No]
Chapter 32. Using Point-to-Point Protocol Interfaces	459