1. Module 3
Configuring a Router

2. CLI Command Modes

3. Basic Steps to Configure a Router
Configure hostname
Configure passwords
Enable / enable secret
Console (con 0)
Virtual terminal (vty)
Configure interfaces
Configure routing protocol
Configure hostname table

4. Configuring the Router Hostname
Router#config t
Router(config)#hostname Router_A
Router_A(config)#exit / end
Router_A#

5. Password Configuration
Passwords are set for:
privileged EXEC mode
Enable password (not used if secret password is set)
Enable secret password (restricts going from user to privileged)
line passwords
console interface
VTY or virtual terminals

6. Password Configuration
Setting Passwords are set for:
privileged EXEC mode
Enable password
Router(config)#enable password cisco
Enable secret password
Router(config)#enable secret class

7. Password Configuration
Setting Passwords are set for:
line passwords
console interface
Router(config)#line console 0
Router(config-line)#password cisco
Router(config-line)#login
VTY (virtual terminals)
Router(config)#line vty 0 4

8. Password Configuration
Password Encryption
The service password-encryption command may be used to set passwords to not display in clear text when viewing running configuration.
Router(config)#line console 0
Router(config-line)#password cisco
Router(config-line)#login
Router(config-line)#service password-encryption
Secret password is always encrypted even when the command above is not used

9. Password Configuration
If no password is set for virtual terminal sessions, no one can log into the router using a virtual terminal session
Password Configuration
Can set 5 different passwords for the VTY lines

10. show commands show interfaces – stats on the router interfaces
show controllers serial – hardware info re: serial interfaces
show clock – Shows the wall-time clock 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 – history of commands executed
show flash – info about flash memory and its IOS

11. show commands show version – info about router and IOS running in RAM
show ARP – Displays the ARP table of the router
show protocol – Displays the global and interface specific status of each configured Layer 3 protocol
show startup-configuration – Displays the saved configuration located in NVRAM
show running-configuration – Displays the configuration currently in RAM

12. Configuring a serial interface

13. Configuring a serial interface
Router#config t
Router(config)#interface serial 0/0
Router(config-if)#ip address
Router(config-if)#clock rate (if DCE is connected)
Router(config-if)#no shutdown
A router is by default administratively down, until it is brought up
A router is by default a DTE device – If connecting one router to another one interface must define the clock – the DCE end of the cable (wire).
The cable is the determining factor with regard to DTE or DCE not the router. One end of the cable is always a DTE and the other is always a DCE.

14. Configuring a router
Both steps are used to remove an existing configuration

15. Configuring an Ethernet interface
Ethernet (on a 2500)
Router#config t
Router(config)#interface ethernet 0
Router(config-if)#ip address
Router(config-if)#no shutdown
FastEthernet (on a 2600)
Router#config t
Router(config)#interface fastethernet 0/0
Router(config-if)#ip address
Router(config-if)#no shutdown

16. Importance of Configuration Standards
Helps reduce complexity
Limits unplanned downtime
Limits events that may impact network performance

17. Interface Descriptions
Identifies important information as to what the interface is connected to
Belfast#config t
Belfast(config)#interface serial 0/0
Belfastconfig-if)#description WAN link to San Antonio
Belfast(config-if)#ip address
Belfast(config-if)#no shutdown

18. Login Banners
They are seen by everyone (telnet, AUX port, console port)
Can convey message to all users
Might want to include a warning not to access the device
Use a delimiting character before and after “ # “
Router#config t
Router(config)#banner motd # Authorized Users Only!!! #

19. Host Name Resolution A global configuration command
Router(config)# ip host name ip addresses
Router(config)# ip host Dallas
Matches static name with IP address
Might think of it as a convenience – not necessary, but convenient to use names instead of addresses
Instead of using telnet or ping
just use telnet name or ping name

20. TFTP SERVER Used to save a copy of the configuration on a computer
Router#copy running-config tftp
Software has to be set up beforehand and running
You will be prompted for information about IP address of tftp server and the file name

21. Saving Configuration Files

22. Module 3
Configuring a Router
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