Basic Router Configuration
When configuring a router, certain basic tasks are performed including:
Naming the router
Configuring a banner
Saving changes on a router
Verifying basic configuration and router operations
You should already be familiar with these configuration commands; however, we will do a brief review. We begin our review with the assumption that the router does not have a current startup-config file.
The first prompt appears at user mode. User mode allows you to view the state of the router, but does not allow you to modify its configuration. Do not confuse the term “user” as used in user mode with users of the network. User mode is intended for the network technicians, operators, and engineers who have the responsibility to configure network devices.
The enable command is used to enter the privileged EXEC mode. This mode allows the user
to make configuration changes on the router. The router prompt will change from a “>” to a “#” in this mode.
Hostnames and Passwords
The figure shows the basic router configuration command syntax used to configure R1 in the following example. You can open Packet Tracer Activity 1.2.2 and follow along or wait until the end of this section to open it.
First, enter the global configuration mode.
Next, apply a unique hostname to the router.
Now, configure a password that is to be used to enter privileged EXEC mode. In our lab environment, we will use the password class. However, in production environments, routers should have strong passwords. See the links at the end of this section for more information on creating and using strong passwords.
Router(config)#enable secret class
Next, configure the console and Telnet lines with the password cisco. Once again, the password cisco is used only in our lab environment. The command login enables password checking on the line. If you do not enter the command login on the console line, the user will be granted access to the line without entering a password.
R1(config)#line console 0
R1(config)#line vty 0 4
Configuring a Banner
From the global configuration mode, configure the message-of-the-day (motd) banner. A delimiting character, such as a “#” is used at the beginning and at the end of the message. The delimiter allows you to configure a multiline banner, as shown here.
R1(config)#banner motd #
Enter TEXT message. End with the character ‘#’.
WARNING!! Unauthorized Access Prohibited!!
Configuring an appropriate banner is part of a good security plan. At a very minimum, a banner should warn against unauthorized access. Never configure a banner that “welcomes” an unauthorized user.
Router Interface Configuration
You will now configure the individual router interfaces with IP addresses and other information. First, enter the interface configuration mode by specifying the interface type and number. Next, configure the IP address and subnet mask:
R1(config-if)#ip address 192.168.2.1 255.255.255.0
It is good practice to configure a description on each interface to help document the network information. The description text is limited to 240 characters.