Summary

Summary

This page summarizes the topics discussed in this module.

A router has several modes that are used to accomplish specific tasks. The user EXEC mode is used primarily to check the status of a router. The privileged EXEC mode allows administrators to set usernames and passwords for access to router commands. Global configuration mode is used to apply configuration statements that affect a whole system.

One of the first configuration tasks is to give a unique name to a router. For security purposes, passwords and user IDs for authorized users should be set. The show command is used to examine the contents of files and for troubleshooting.

Serial interfaces require a clock signal to control the timing of the communications. An interface must have an IP address and subnet mask to route IP packets. By default, interfaces are turned off or disabled. Use the no shutdown command to turn on an interface. Use the show running-config command to display the current running configuration to verify any modifications.

Configuration standards are developed for consistency, to reduce network complexity, to reduce downtime, and to maximize network performance. Some standards for configuration files include the number of files to maintain, how they are stored, and where they are stored. Interface descriptions, login banners, and MOTDs can be standardized to inform users about events such as downtime and to warn unauthorized users.

Host name resolution translates names to IP addresses. The Cisco IOS software maintains a cache of host name-to-address mappings for use by EXEC commands. The cache speeds up the conversion process. Unlike DNS, host names are only significant to the router on which they are configured. Host names are entered in global configuration mode.

Configuration backup can be stored on a TFTP server, on a network server, or on a disk. A specific backup plan will ensure that the files are available if a problem occurs.