1

Pertemuan 5 Configuring a Router

Discussion Topics

• CLI command modes• Configuring a router name• Configuring router passwords• Examining the show commands• Configuring a serial interface• Making configuration changes• Configuring an Ethernet interface

2

Command-Line InterfaceCommand Modes

Configuring a Router Name

5

Configuring a router name

Router#config t

Router(config)#hostname Tokyo

Tokyo(config)#

Mistake…

Should be…

Configuring Router Passwords

7

WARNING• service password-encryption uses a Cisco Level 7

encryption which is very easy to decrypt.• For the GetPass! software www.boson.com• However, the enable secret <password> uses a stronger

encryption method and cannot be easily hacked.

service password-encryption command

8

Examining the show commands

• show interfaces – Displays all the statistics for all the interfaces on the router. To view the statistics for a specific interface, enter the show interfaces command followed by the specific interface and port number.

• show controllers serial – Displays information-specific to the interface hardware

• show clock – Shows the time set in the router • show hosts – Displays a cached list of host names and addresses • show users – Displays all users who are connected to the router • show history – Displays a history of commands that have been

entered

Examining the show commands

• show flash – Displays information about flash memory and what IOS files are stored there

• show version – Displays information about the router and the IOS that is running in RAM

• show ARP – Displays the ARP table of the router • show protocol – Displays the global and interface

specific status of any configured Layer 3 protocols • show startup-configuration – Displays the saved

configuration located in NVRAM • show running-configuration – Displays the

configuration currently running in RAM

9

Examining the show Commands

• Many show commands can be used to examine the contents of files in the router and for troubleshooting.

• In both privileged EXEC and user EXEC modes, the command show ? provides a list of available show commands.

Interface Configuration Commands

Configuring an Ethernet Interface

13

show ip interface command

• A serial interface will not show “up” and “up” unless both ends are properly configured (mostly) and a the no shutdown command is used.

• If one router’s configuration looks okay, check the other router’s

configuration.

Router# show ip interface brief

Interface IP-Address OK? Method Status Protocol

Ethernet0 131.108.1.11 YES manual up up

Serial0 198.135.2.49 YES manual administratively down down

What is wrong here? The administrator has either done a “shutdown” on the interface or has forgotten to do a “no shutdown”.

14

Lab

Real world

• On serial links that are directly interconnected, as in a lab environment, one side must be considered a DCE and provide a clocking signal.

• The clock is enabled and speed is specified with the clock rate command.

Router(config)#interface serial 0/0

Router(config-if)#clock rate 56000

Router(config-if)#no shutdown

Configuring a serial interface

Rick Graziani graziani@cabrillo.edu

15

RouterB(config)#inter serial 1RouterB(config-if)#clock rate ? Speed (bits per second) 1200 2400 4800 9600 19200 38400 56000 64000 <text omitted> 2000000 4000000

<300-4000000> Choose clockrate from list above

RouterB(config-if)#clock rate 64000RouterB(config-if)#

RouterB DCE cable

RouterA DTE cable

Configuring a serial interface

16

How can you tell which end is the DTE and which end is the DCE? Look at the label on the cable. Look at the connecter between the two cables - The DTE cable will

always be male and the DCE cable will always be female.

DTE Cable DCE Cable

Configuring a serial interface

17

RouterA#show controllers serial 0HD unit 0, idb = 0xECA4C, driver structure at 0xF1EC8buffer size 1524 HD unit 0, V.35 DTE cablecpb = 0x62, eda = 0x403C, cda = 0x4050RX ring with 16 entries at 0x62400000 bd_ptr=0x4000 pak=0x0F5704 ds=0x62FFB8 status=80 pak_size=22

RouterB#show controllers serial 0buffer size 1524 HD unit 0, V.35 DCE cable, clockrate 64000cpb = 0x62, eda = 0x408C, cda = 0x40A0RX ring with 16 entries at 0x62400000 bd_ptr=0x4000 pak=0x0F2F04 ds=0x627908 status=80 pak_size=22

RouterB DCE cable

RouterA DTE cable

This is one of few commands where there must be a space between the interface type and the port.

Configuring a serial interface

18

• Please be very careful when connecting the male and female V.35 cables together AND when connecting the serial cable to the router!

• They only connect ONE WAY!• Be sure the two ends match!• Don’t force it!

This end up!

(The wider end is up.)

Configuring a serial interface

19

running-config

IOS (running)

startup-config IOS

ios (partial)Bootup program

Executing adds, moves, and changes