router basic configuration

7/26/2019 Router Basic configuration

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Router ConfigurationBasics


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Overview Router configuration controls the operationof the routers:

Interface IP address and netmask

Routing information (static, dynamic ordefault)Boot and startup informationSecurity (passwords and authentication)


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Where is the Configuration?Router always has two configurations:

Running configuration

Startup confguration


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Where is the Configuration?Running configuration:

In RAM, determines how the router iscurrently operatingIs modified using the configure commandTo see it: show running-config

Startup confguration:

In NVRAM, determines how the router willoperate after next reloadIs modified using the copy commandTo see it: show startup-config


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Where is Startup Configuration?Can also be stored in more permanent places:

External hosts, using TFTP (Trivial File TransferProtocol)

In flash memory in the router

Copy command is used to move it around:

copy run start copy run tftp

copy start tftp copy tftp start

copy flash start copy start flash


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Router Access ModesUser EXEC mode: Limited, show only

Router>

Privileged EXEC mode: Detailed---configuration of router, debugging, testing,file manipulationetc.

Router#

ROM Monitor useful for password recovery

& new IOS upload session

Setup Mode available when router has nostartup-config file


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Network Configuration Modes

User EXECMode

Router>

PrivilegedMode Router#

GlobalConfiguration

Mode

Router(config)#

SpecificConfiguration

Mode

Router(config-xx)


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Router Prompts How to tell where you are on the router

You can tell in which area of the routers configurationyou are by looking at the router prompts:

Router> USER prompt mode

Router# PRIVILEGED EXEC prompt mode

Router(config) terminal configuration prompt

Router(config-if) interface configuration prompt

Router(config-subif) sub-interface configurationprompt


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Logging into the RouterConnect router to console port or telnet torouter.

router> router>enable

password router#router#?

Configuring the router: To configure router

parameters need to load into RAM.router# configure terminalrouter(config)#


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Logging into the RouterConfiguring the router: To configure routerparameters need to load into RAM.

router# configure terminalrouter(config)#


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Check & Adjust Clock

RouterA# show clockRouterA# clock ?RouterA# clock set?RouterA# clock set 13:03:10?RouterA# clock set 13:03:10 9?RouterA# clock set 13:03:10 9 Feb?RouterA# clock set 13:03:10 9 Feb 2016RouterA# show clock


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Name Your RouterRouterA> ----- User ModeRouterA>enableRouterA# ----- Privileged Mode

To configure router parameters, needto enter into RAM---

RouterA# Configure TerminalRouterA(config)#

Personalized your Router Identity ---RouterA(config)# Hostname (Name)


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Setting PasswordNumber one priority to make sure youhave set this password on your router.To set Global password do the following:

Enter into Global configuration Mode---RouterA# Configure TerminalRouterA(config)#RouterA(config)# enable password (your password)

OR

RouterA(config)# enable secret (your password)


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Setting PasswordTo set user mode password for theconsole line, perform the following:

RouterA# Configure TerminalRouterA(config)#RouterA(config)# line console 0RouterA( config-line )# LoginRouterA( config-line )# Password ( yourpassword)


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Setting PasswordTo set this password for users accessingthe router remotely via telnet, performthe following:

RouterA# Configure TerminalRouterA(config)#RouterA(config)# line vty 0 4

RouterA( config-line )# LoginRouterA( config-line )# Password ( yourpassword)

* line vty [first line number] [last line number] command. By default, Cisco IOS enables 5 virtualterminal lines lines 0 through 4.


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Review

Set Clock

Set BannerSet Password

Configure Interfaces


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Interface ConfigurationTypes of interfaces ----

GigabitEthernet interface

FastEthernet interfaceEthernet interfaces

Serial interfaces


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Interface ConfigurationInterfaces are named by typeslot/port; e.g. :

ethernet0, ethernet1,... Ethernet5/1

Serial0/0, serial1 ... Serial3

Can be abbreviated:ethernet0 or eth0 or e0Serial0/0 or ser0/0 or s0/0FastEthernet0/0 or fe0/0GigabitEthernet0/1 or ge0/1


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Interface ConfigurationBy default interfaces are down.

Need to enable after configuration.

router( config-if )#no shutdown

To disable any interface.router( config-if )#shutdown

Descriptionrouter( config-if )#description ethernetlink to admin building router


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Interface ConfigurationConfiguring Ethernet interface:

RouterA# config terminal

RouterA(config)#interface ethernet 0/0RouterA(config-if)# Description xxxxxRouterA(config-if)# ip address n.n.n.n

m.m.m.m

RouterA(config-if)#no shutdownRouterA(config-if)#exitRouterA#


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Interface ConfigurationConfiguring FastEthernet interface:


RouterA(config)#interface fastethernet 0/0RouterA(config-if)# Description xxxxxRouterA(config-if)# ip address n.n.n.n

m.m.m.m



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Interface ConfigurationConfiguring GigabitEthernet interface:


RouterA(config)#interface ge 0/0RouterA(config-if)# Description xxxxxRouterA(config-if)# ip address n.n.n.n

m.m.m.m



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Interface ConfigurationConfiguring Serial interface:


RouterA(config)#interface serial 0/0/0RouterA(config-if)# Description xxxxxRouterA(config-if)# ip address n.n.n.n

m.m.m.m



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Saving Configuration ParametersAll the changes are performed onrunning configuration file ie. RAM.Need to store those changes atNVRAM/Flash for using in next reload.

RouterA#copy running-config startup-configOR

RouterA# copy run start


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Review

Set ClockSet Banner

Set PasswordInterface Configuration

Save ConfigurationBackup Configuration


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5 Frequent IOS Commands(1)To know what interfaces are on yourrouter, important statistics about thoseinterfaces, and whether they are up ordown.

RouterA# show interfaces


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5 Frequent IOS Commands(2)Whatever configuration changes, needto save those changes. This commandcopies the configuration in RAM that youhave been modifying to theconfiguration in flash

RouterA# copy running-configstartup-config

OR RouterA# copy run start

OR

RouterA# wr (Write Memory)


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5 Frequent IOS Commands(3)Once you know that your interfaces areup and you have saved yourconfiguration, you need to know --- areyour routing protocols working?

RouterA# show ip route


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5 Frequent IOS Commands(4)

To get the the best summary of thestatus and IP addresses of yourinterfaces, use following ---

RouterA# show ip interface brief


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5 Frequent IOS Commands(5)

To see the entire routers configurationie. to see the IP addresses, interfaces,passwords (that are in clear text),

routing protocols, and other settings..

RouterA# show running config


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IOS Commands - show There is one privileged mode commandthat you will find yourself usingextensively for:

Viewing routers configurationVerifying interfaces configurationViewing interfaces status

RouterA# show running configurationRouterA# show clockRouterA# show interfacesRouterA# show ip interfaces brief

RouterA# show interfaces description


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Configuring your RouterSet the enable (secret) password:

router(config)# enable secret your pswd

This MD5 encrypts the password

The old method was to use the enable password command. But this is not secure (weak encryption) andis ABSOLUTELY NOT RECOMMENDED. DO NOT USE!

Ensure that all passwords stored on router are(weakly) encrypted rather than clear text:

router(config)# service password-encryption


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The NO CommandUsed to reverse or disable commands e.g

ip domain-lookup

no ip domain-lookup

ip address 1.1.1.1 255.255.255.0no ip address


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Getting Help


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Getting Online HelpIOS has a built-in help facility;

use ? to get a list of possible configurationstatements

? after the prompt lists all possiblecommands:router#?

? lists all possiblesubcommands, e.g.:

router#show ?router#show ip ?


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Getting Online Help ? shows all possible commandcompletions

router#con?

configure connect


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Getting Online HelpThis also works in configuration mode:router(config)#ip a?

accounting-list accounting-threshold

accounting-transits address-poolalias as-path

router(config)#int e0/0

router(config-if)#ip a?access-group accounting address


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Getting Online HelpCan explore a command to figure out the syntax:

router(config-if)#ip addr ? A.B.C.D IP address

router(config-if)#ip addr n.n.n.n ? A.B.C.D IP subnet mask

router(config-if)#ip addr n.n.n.n m.m.m.m ?secondary Make this IP address a secondary address

router(config-if)#ip addr n.n.n.n m.m.m.m router(config-if)#


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Getting Lazy Online HelpTAB character will complete a partial wordhostel-rtr(config)#int hostel-rtr(config)#interface et hostel-rtr(config)#interface ethernet 0

hostel-rtr(config-if)#ip add hostel-rtr(config-if)#ip address n.n.n.n m.m.m.m

Not really necessary; partial commands can beused:router#conf trouter(config)#int e0/0router(config-if)#ip addr n.n.n.n


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Getting Lazy Online HelpCommand history

IOS maintains short list of previously typed commands

up- arrow or ^p recalls previous command

down-arrow or ^n recalls next command

Line editing

left-arrow, right-arrow moves cursor inside command

^d or backspace will delete character in front of cursor

Ctrl-a takes you to start of line

Ctrl-e takes you to end of line


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Backing Up Router ConfigurationRunning configuration can be backedup into TFTP server or some otherlocations.

RouterA# copy run tftp --- to copy the runningconfiguration into FTFT server.

Address or name of remote host []?172.16.10.2 the ip address of TFTP

serverDestination filename [routername-confg]?/Backup/Router01.cfg the folder path on theserver where the configuration file will be stored)


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Restore Router Configuration

RouterA# show run --- to see the runningconfigurationRouterA# copy tftp run --- to copy theconfiguration file from TFTP server to the runningconfiguration of the router/RAMAddress or name of remote host []? 172.16.10.2 TFTP server addressSource filename[]? /Backup/Router01.cfg the configuration file to be copied to the router[router name]# show run[router name]# show interfaces[router name]# copy run start


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View ConfigurationUse show running-configuration to seethe current configuration

Use show startup-configuration to see

the configuration in NVRAM, that willbe loaded the next time the router isrebooted or reloaded


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What Next?????


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Deleting your Routers Configuration

To delete your routers configuration

Router#erase startup-config

OR Router#write eraseRouter#reload

Router will start up again, but in setupmode, since startup-config file does notexists


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Cisco RouterConfiguration Basics

Questions?

router basic configuration

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