Cisco Systems 1900 Series Gateway of Last Resort

5-15

Cisco 1900 Series Hardware Installation

OL-19084-02

Chapter 5 Configuring the Router

Performing the Initial Configuration on the Router

Gateway of Last Resort

When default information is being passed along through a dynamic routing protocol, no further

configuration is required. The system periodically scans its routing table to choose the optimal default

network as its default route. In the case of RIP, there is only one choice, network 0.0.0.0. In the case of

IGRP, there might be several networks that can be candidates for the system default. The Cisco IOS

software uses both administrative distance and metric information to determine the default route

(gateway of last resort). The selected default route appears in the gateway of last resort display of the

show ip route EXEC command.

If dynamic default information is not being passed to the software, candidates for the default route are

specified with the ip default-network global configuration command. In this usage, the ip

default-network command takes an unconnected network as an argument. If this network appears in the

routing table from any source (dynamic or static), it is flagged as a candidate default route and is a

possible choice as the default route.

If the router has no interface on the default network, but does have a route to it, it considers this network

as a candidate default path. The route candidates are examined and the best one is chosen, based on

administrative distance and metric. The gateway to the best default path becomes the gateway of last

resort.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip routing

4. ip route dest-prefix mask next-hop-ip-address [admin-distance] [permanent]

5. ip default-network network-number

or

ip route dest-prefix mask next-hop-ip-address

6. end

7. show ip route

DETAILED STEPS

Command or Action Purpose

Step 1 enable

Example:

Router> enable

Enables privileged EXEC mode.

• Enter your password if prompted.

Step 2 configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 ip routing

Example:

Router(config)# ip routing

Enables IP routing.

Contents

Main Page CONTENTS OL-19084-03 i Page Page Page Preface Objectives Audience Organization Conventions ix damage or loss of data. the paragraph. x xi xii Page xiv Related Documentation Searching within Cisco Documents Obtaining Documentation and Submitting a Service Request Overview of the Router Safety Warnings Safety Warnings for Finland, Norway and Sweden Chassis Views Page 123 4 5 Hardware Features Product Serial Number Location Cisco Product Identification Tool Built-In Interfaces Removable, Interchangeable, and Optional Modules Memory LED Indicators Page Chassis Ventilation Real-Time Clock Chassis Security Wireless LAN Connectivity Baud Reset Button Interface Numbering Specifications Page Page Page Regulatory Compliance Preparing for Router Installation Safety Recommendations General Guidelines Safety with Electricity Preventing Electrostatic Discharge Damage General Site Requirements Power Supply Considerations Site Environment Site Configuration Wireless LAN Considerations Inspecting the Router Installation Checklist Site Log Required Tools and Equipment for Installation and Maintenance Page Cable Information and Specifications for Cisco 1900 Series Routers Console and Auxiliary Port Considerations About Console and Auxiliary Ports Console Port Connections EIA/TIA-232 Port USB Serial Console Auxiliary Port Connections Preparing to Connect to a Network Ethernet Connections Serial Connections About Serial Connections Configuring Serial Connections Serial DTE or DCE Devices Signaling Standards Supported Transmission Speeds and Distance Limitations Asynchronous/Synchronous Serial Module Baud Rates ISDN BRI Connections CSU/DSU Connections Installing and Connecting the Router About Modules Internal Modules Plug-In Modules Safety Warnings Safety Warnings for Finland, Norway and Sweden Setting Up the Chassis Chassis Airflow Diagram Setting the Chassis on a Desktop Chassis Grounding Wall-Mounting the Chassis Page Page Rack-Mounting the Chassis Attaching Rack-Mount Brackets to Cisco 1900 Series Routers 4-8 Figure 4-5 Bracket Installation for Front Mounting the Cisco 1905 and Cisco 1921 ISRs Figure 4-6 shows how to attach the brackets to the sides of the router with the back panel forward. Figure 4-6 Bracket Installation for Back Mounting the Cisco 1905 and Cisco 1921 ISRs Figure 4-7 shows how to attach the brackets to the sides of the router with the front panel forward. Installing the Chassis Ground Connection Page Connecting WAN and LAN Cables Safety Messages 4-12 Ports and Cabling Connection Procedures and Precautions Connecting to a Console Terminal or Modem Connecting to the Console Port with Microsoft Windows Page Connecting to the Console Port with Mac OS X Connecting to the Console Port with Linux Installing the Cisco Microsoft Windows USB Device Driver Installing the Cisco Microsoft Windows XP USB Driver Installing the Cisco Microsoft Windows 2000 USB Driver Installing the Cisco Microsoft Windows Vista USB Driver Uninstalling the Cisco USB Driver Uninstalling the Cisco Microsoft Windows XP and 2000 USB Driver Using the Add Remove Programs Utility Using the Setup.exe Program Uninstalling the Cisco Microsoft Windows Vista USB Driver Connecting to the Auxiliary Port Connecting Power Connecting to AC Power Connecting to DC Power DC Wiring Requirements for Cisco 1900 Series Routers Cisco 1900 Series Router Wiring Procedure for DC Input 4-24 Page Page Configuring the Router Powering up the Router Checklist Before Powering Up the Cisco Router Powering Up the Cisco Router Verifying the Front Panel LED Indications Performing the Initial Configuration on the Router Using the Cisco Setup Command Facility Page 5-5 Step 9 Select one of the available interfaces for connecting the router to the management network: Step 10 Respond to the following prompts as appropriate for your network: The system creates the following configuration command script: Step 11 Respond to the following prompts. Select 2 to save the initial configuration: Using Cisco Configuration Professional Express Using the Cisco CLIManual Configuration Initial CLI Configuration Configuring the Router Hostname Configuring the Enable and Enable Secret Passwords Restrictions Configuring the Console Idle Privileged EXEC Timeout Page Configuring Gigabit Ethernet Interfaces Page Specifying a Default Route or Gateway of Last Resort Configuring IP Routing and IP Protocols IP Routing Default Routes Default Network Gateway of Last Resort 5-16 Command or Action Purpose Specifying a Default Route: Example Sample Output for the show ip route Command Step 4 ip route dest-prefix mask next-hop-ip-address Configuring Virtual Terminal Lines for Remote Console Access Example What to Do Next Configuring the Auxiliary Line Verifying Network Connectivity Prerequisites Page Saving Your Router Configuration Saving Backup Copies of Configuration and System Image Page Verifying the Initial Configuration Page Getting Software Licenses for the Router Activating a New Software Package or Feature RMA License Transfer Additional Information