Specifications

Configuring Asynchronous Lines and Interfaces
How to Configure Other Asynchronous Line and Interface Features
DC-32
Cisco IOS Dial Technologies Configuration Guide
Using Advanced Addressing Methods for Remote Devices
You can control whether addressing is dynamic (the user specifies the address at the EXEC level when
making the connection) or whether default addressing is used (the address is forced by the system). If
you specify dynamic addressing, the router must be in interactive mode and the user will enter the
address at the EXEC level.
It is common to configure an asynchronous interface to have a default address and to allow dynamic
addressing. With this configuration, the choice between the default address or dynamic addressing is
made by the users when they enter the slip or ppp EXEC command. If the user enters an address, it is
used, and if the user enters the default keyword, the default address is used.
This section describes the following optional tasks:
• Assigning a Default Asynchronous Address
• Allowing an Asynchronous Address to Be Assigned Dynamically
Assigning a Default Asynchronous Address
To assign a permanent default asynchronous address, use the following command in interface
configuration mode:
Use the no form of this command to disable the default address. If the server has been configured to
authenticate asynchronous connections, you are prompted for a password after you enter the slip default
or ppp default EXEC command before the line is placed into asynchronous mode.
The assigned default address is implemented when the user enters the slip default or ppp default EXEC
command. The transaction is validated by the TACACS server, when enabled, and the line is put into
network mode using the address that is in the configuration file.
Configuring a default address is useful when the user is not required to know the IP address to gain
access to a system (for example, users of a server that is available to many students on a campus). Instead
of each user being required to know an IP address, they only need to enter the slip default or ppp default
EXEC command and let the server select the address to use.
See the section “Making Additional Remote Node Connections” in the chapter “Configuring
Asynchronous SLIP and PPP” in this publication for more information about the slip and ppp EXEC
commands.
See the following sections for examples:
• Modem Asynchronous Group Example
• Configuring Specific IP Addresses for an Interface
• IP and PPP Asynchronous Interface Configuration Example
Allowing an Asynchronous Address to Be Assigned Dynamically
When a line is configured for dynamic assignment of asynchronous addresses, the user enters the slip or
ppp EXEC command and is prompted for an address or logical host name. The address is validated by
TACACS, when enabled, and the line is assigned the given address and put into asynchronous mode.
Command Purpose
Router(config-if)# peer default ip address ip - address
Assigns a default IP address to an asynchronous interface.