Passwords to secure your Cisco Router.

Types of Cisco Router Passwords

When it comes to basic password security, there are three basic types:

• Line Passwords
• Privileged mode Passwords (enable mode)
• Username Passwords (optional)

Let’s explore these.

Line Passwords

Line passwords are configured on router lines. Examples of lines are:

• Console Line - The console is the main serial administrative port on a router. This is where you configure the router when it is new and has no network configuration.

• Aux Line – The aux line is an auxiliary port. Like the console, it is a physical port on every router. You can think of it as a backup console port. Besides being a backup console port, the aux port is periodically used for administrative console dial up access to the router.
• VTY Lines – Vty lines are “virtual tty” lines and are used when you connect to the router via telnet or ssh. These are not physical lines on the router but virtual “inbound network lines”.
• Async Lines – Async lines are asynchronous serial lines and are optional. These async lines are created when you insert an async serial card in a router. You can use the async serial lines to connect dumb-terminals (text-based terminals), serial printers, or modems.
  
  
  
  
  All of these different lines need a password configured on them. Let’s find out how to configure Cisco router line passwords.

  Configuring Cisco Router Line Passwords

  There are two commands used to configure line passwords, no matter what kind of line you are using. The commands are password and login. The password command is used to set your line password. The login command, when entered by itself, is used to tell the router to use the password that is configured on the line. Here is an example of how this is configured on the console port:
  
  
  Router#conf t
  Router(config)#line con 0
  Router(config-line)#password cisco
  Router(config-line)#login
  Router(config-line)#exit
  
  
  We repeat this on AUX port as well
  
  
  Router#conf t
  Router(config)#line aux 0
  Router(config-line)#password cisco
  Router(config-line)#login
  Router(config-line)#exit
  
  
  Finally, we configure the same commands on the VTY lines. The catch to doing this is that there is more than one VTY. Because you don’t want to have to configure them one at a time, you use a VTY range when performing the configuration. Using a VTY range works by specifying your router’s starting and ending VTY number. Inside the configuration mode for this range of VTYs is where you are configuring the password and login commands. In the past, router only had 0-4, or 5, VTY lines. Today, most routers have 0-15, or 16, VTY lines. Make sure that you know how many VTY’s your router has so that there aren’t some lines that are left without a password. Here is what you do to tell how many lines your router has:
  
  
  Router#conf t
  Router(config)#line vty 0 ?
   <1-15>   Last Line Number
  
  
  
  
  The last Number for example 15 lets you know how many VTY lines are on the router...in this case it is 16....
  
  
  for configuration of VTY passwords on the router
  
  
  Router#conf t
  Router(config)#line vty 0 15
  Router(config-line)#password cisco
  Router(config-line)#login
  Router(config-line)#exit