Module 3 Configuring a Router

CLI Command Modes

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

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

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

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

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

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

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

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

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

Configuring a serial interface

Configuring a serial interface Router#config t Router(config)#interface serial 0/0 Router(config-if)#ip address 192.10.10.1 255.255.255.0 Router(config-if)#clock rate 56000 (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.

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

Configuring an Ethernet interface Ethernet (on a 2500) Router#config t Router(config)#interface ethernet 0 Router(config-if)#ip address 192.10.10.1 255.255.255.0 Router(config-if)#no shutdown FastEthernet (on a 2600) Router#config t Router(config)#interface fastethernet 0/0 Router(config-if)#ip address 192.10.10.1 255.255.255.0 Router(config-if)#no shutdown

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

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 192.10.10.1 255.255.255.0 Belfast(config-if)#no shutdown

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!!! #

Host Name Resolution A global configuration command Router(config)# ip host name ip addresses Router(config)# ip host Dallas 192.168.1.23 192.168.2.57 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 192.168.1.23 or ping 192.186.2.57 just use telnet name or ping name

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

Saving Configuration Files

Module 3 Configuring a Router END