| 3.1 |  | Configuring a Router |
| 3.1.3 |  | Configuring router passwords |

| Passwords restrict access to routers. Passwords should always be configured for virtual terminal lines and the console line. Passwords are also used to control access to privileged EXEC mode so that only authorized users may make changes to the configuration file. The following commands are used to set an optional but recommended password on the console line: Router(config)#line console 0 Router(config-line)#password <password> Router(config-line)#login A password must be set on one or more of the virtual terminal (VTY) lines for users to gain remote access to the router using Telnet. Typically Cisco routers support five VTY lines numbered 0 through 4, although different hardware platforms support different numbers on VTY connections. Often the same password is used for all lines but sometimes one line is set uniquely to provide a fall-back entry to the router if the other four connections are in use. The following commands are used to set the password on the VTY lines: Router(config)#line vty 0 4 Router(config-line)#password <password> Router(config-line)#login The enable password and the enable secret are used to restrict access to the privileged EXEC mode. The enable password is only used if the enable secret has not been set. It is recommended that the enable secret always be set and used because it is encrypted while the enable password is not encrypted. These are the commands that are used to set the enable passwords: Router(config)#enable password <password> Router(config)#enable secret <password> Sometimes it is undesirable for passwords to be shown in clear text in the output from the show running-config or show startup-config commands. This command is used to encrypt passwords in configuration output: Router(config)#service password-encryption The service password-encryption command applies a weak encryption to all unencrypted passwords. The enable secret <password> command uses a strong MD5 algorithm for encryption.
| Lab Activity Lab Exercise: Configuring Router Passwords This lab is to configure a password for console login to user mode and configure a password for virtual terminal (Telnet) sessions.
| Lab Activity e-Lab Activity: Configuring Router Passwords In this lab, the student will configure passwords for the console, virtual terminals, and a secret password .
| Lab Activity e-Lab Activity: Command-line Interface Command Modes In this lab, the students will learn to enter some of the most common modes the router supports.
| Web Links Passwords and Privileges Commands http://www.cisco.com/en/US/products/sw/ iosswrel/ps1835/products_command_reference_ chapter09186a00800ca7cd.html#1017603