Enterasys Networks Security Router X-PeditionTM - Manual (Page 240)

Dialer Interface Spoofing
10-18 Configuring Dialer Services
For more information on ISDN fundamentals, refer “Configuring Integrated Services Digital
Network” on page 1 and the XSR CLI Reference Guide.
Dialer Interface Spoofing
Spoofing on a dialer interface is defined as the line “pretending” to be up when it is not. That is,
the line is physically disconnected but the route entry is maintained in the routing table so that
when a call is initiated, it is processed promptly, preserving the on-demand nature of the line.
The XSR’s dialer interface supports three modes of operation:
• Non-spoofed - the dialer interface is down as long as there is no active dialup connection.
• Spoofed point-to-point - the dialer interface is always up and visible in the node's routing table.
• Spoofed point-to-multipoint - the dialer interface is up and can be directly connected to multiple
neighbors.
You set the dialer interface mode when the interface is first created. The mode is configured with
the following commands:
• interface dialer number — This is the default, spoofed point-to-point interface mode of
operation used for backup and dial-on-demand purposes.
• interface dialer number multi-point — In spoofed point-to- multipoint mode, this
option is used for on-demand applications.
Additionally, the dialer map ip command is available in spoofed multi-point mode only and,
configured as such, the dialer interface IP address cannot be negotiated.
Dialer Watch
The XSR’s Dialer Watch feature backs up each route in the routing table. Backed up routing table
entries can be:
• Local routes (owned by one of the XSR’s physical interfaces)
• Static routes
• RIP learned routes
• OSPF learned routes
Routes requiring backup are configured with the dialer watch-list command as a collection of
entries. Watch lists are identified by the watch-list number – a unique number for one particular
XSR.
The XSR’s backup functionality is implemented by the Dialer subsystem and configured under
Interface dialer mode. Each dialer interface used to back up watched routes must be configured
with one or more dialer watch-groups, by the
dialer watch-group command, linked to each
other by the same number.
Note: Optional commands shown in sample configurations are preceded by an exclamation point.
Note: The dialer interface cannot be used for on-demand applications while operating in non-
spoofed mode.