Configuring a Router MM Clements. Copyright 2003 This Week Command line interface Router configuration Modes for configuration Interface

Configuring a Router

MM Clements

Copyright 2003 www.ciscopress.com

This Week

Command line interface Router configuration Modes for configuration Interface configuration Working with configurations using Packet

Tracer 5.x


Conventions used in these notes

All commands e.g. enable will use Courier font to distinguish them from text

After each command has been entered you should press Enter (Return)


Cisco IOS

Internetwork Operating System Accessed via command line only No GUI – makes for increased OS reliability

and lower hardware requirements Has modes for operation unlike Linux or DOS


Command-Line Interface Modes


Global Configuration Modes


Initial login to a router

Power up router System information displayed Begins in User Executive mode Users can do little (damage!) here Enter Privileged Executive mode with enable

command May be password protected User will be prompted if necessary


Router Boot Process

Router decompresses IOS image from Flash memory

Legal information is displayed On first ever ( or clean ) boot, user is asked

whether or not to enter configuration dialogue This is for non-Cisco educated people –

answer n ( for NO )


System Bootstrap, Version 12.1(3r)T2, RELEASE SOFTWARE (fc1)Copyright (c) 2000 by cisco Systems, Inc.cisco 2620 (MPC860) processor (revision 0x200) with 60416K/5120K bytes of

memory

Self decompressing the image :#########################################################################

# [OK]

Restricted Rights Legend

Use, duplication, or disclosure by the Government issubject to restrictions as set forth in subparagraph(c) of the Commercial Computer Software - RestrictedRights clause at FAR sec. 52.227-19 and subparagraph(c) (1) (ii) of the Rights in Technical Data and Computer

Software clause at DFARS sec. 252.227-7013. Cisco Systems, Inc. 170 West Tasman Drive San Jose, California 95134-1706


Clean Boot Continued--- System Configuration Dialog ---

Continue with configuration dialog? [yes/no]: n

Press RETURN to get started!

Router>?Exec commands: <1-99> Session number to resume connect Open a terminal connection disable Turn off privileged commands disconnect Disconnect an existing network connection enable Turn on privileged commandsEtc. etc.


Learning the Commands

Unlike Linux and DOS, all commands available can be accessed using a question mark ( ? ) – displays minor help too

This allows all or partially typed commands to be shown

E.g. to show all commands that begin with the letter ‘c’ type c? at the prompt and press enter (return)


Getting Going

In User Exec the prompt is Router> From User Exec proceed to Privileged Exec

using the enable command Now you are in Privileged Exec the prompt is Router#

This mode allows many parameters of the router to be viewed

These can be seen using a show command


Examining the show Commands

There are many show commands that display the settings for the router– Also useful for troubleshooting

In both Privileged EXEC and User EXEC modes, the command show ? provides a list of available show commands


Making Changes to the Router

To change settings you need to enter Global Configuration mode

This can be achieved using the configure terminal command

The prompt now changes to Router(config)# A different set of commands are now available Many configuration modes exist too


Configuring a Router Name

A router should have a name to allow it to be easily identified

The location is a good choice but any name can be set

Router(config)#hostname ChathamChatham(config)#

The router’s security should be considered too


Router Identification Configuration


Password Configuration


Configuring an Ethernet Interface

1. Enter global configuration mode2. Enter interface configuration mode3. Specify the interface address and subnet

mask4. Enable the interface


Setting FastEthernet Interface

Router(config)#interface FastEthernet 0/0Router(config-if)#ip address 192.168.1.1 255.255.255.0

Router(config-if)#no shutdown

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up

Router(config-if)#


What interfaces does the router have?

You need to use a show command show ip interface brief will list all

interfaces of the router The names of the interfaces must be entered

to make changes to the interfaces of the router


Router#show ip interface brief

Interface IP-Address OK? Method Status Protocol FastEthernet0/0 unassigned YES unset administratively down down FastEthernet0/1 unassigned YES unset administratively down down Serial0/0 unassigned YES unset administratively down down Serial0/1 unassigned YES unset administratively down down


Interface Configuration Commands


Interface Descriptions

An interface description should be used to identify important information such as a distant router, a circuit number, or a specific network segment.


Adds, Moves, and Changes


Finishing the Configuration

Once finished you should type the exit command to return one step back in the command mode structure

To immediately return to Priv Exec, type the end command

Now you need to save the configuration or if power is lost, the configuration is lost


Saving the Configuration

When in Global Config mode, you are writing directly to DRAM

The contents of DRAM can be accessed using the running-config file but are lost if the power is turned off

The Priv Exec command copy running-config startup-config saves the contents of DRAM to NVRAM for the next reboot


Checking you have saved properly

After issuing the copy running-config startup-config hcommand the router displays the following

Router#copy running-config startup-config Destination filename [startup-config]? Building configuration...[OK]Router#


Rebooting the router

At Priv Exec prompt, issue the reload command and confirm (Enter)

The router restarts but no longer displays the same question about initial configuration

You should be able see all of the information that you entered when in Priv Exec again

Type the show running-config command and examine the output


Conclusion

Cisco IOS allows command line modification A ? allows commands to be displayed CLI has modes for configuration Need to be in the right mode to make changes running-config file is the contents of DRAM startup-config file is used to store router’s

configuration for the next boot

Documents

Configuring a Router MM Clements. Copyright 2003 This Week Command line interface Router configuration Modes for configuration Interface