Configuring a Router

Understanding LED indicators on the router

•This green light means that the system is on and has initialized properly.

•An interface LED indicates the activity of the corresponding interface.

•A problem may be indicated if an LED is off

CLI Command Modes

Basic Steps to Configure a Router

1. Configure hostname

2. Configure passwords

• Enable / enable secret

• Console

• Virtual terminal (vty)

3. Configure interfaces

4. Configure routing protocol

Configuring the Router Hostname

Router#config t

Router(config)#hostname Router_A

Router_A(config)#exit

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 password

• Enable secret password – Router(config)#enable secret password

Password Configuration

• Setting Passwords are set for:– line passwords

• console interface– Router(config)#line console 0– Router(config-line)#password password– Router(config-line)#login

• VTY or virtual terminals– Router(config)#line vty 0 4– Router(config-line)#password password– Router(config-line)#login

Password Configuration

• Password Encryption may set– 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 password– Router(config-line)#login – Router(config-line)#service password-encryption

– Secret password is always encrypted even when the command above is not used

Password ConfigurationIf no password is set for virtual terminal sessions, no one can log into the router using a virtual terminal session

show commands

• show interfaces – stats on the router interfaces• show controllers serial – hardware info re serial

interfaces• 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 – history of commands• show flash – info about flash memory and the IOS’s

stored there

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 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

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!!! #