Host name resolution / Configuring host tables / Configuration backup and documentation

Host name resolution

3.2.6  This page will explain how Cisco IOS performs host name resolution.

Host name resolution is the process that a computer system uses to associate a host name with an IP address.

In order to use host names to communicate with other IP devices, network devices such as routers must be able to associate the host names with IP addresses. A list of host names and their associated IP addresses is called a host table.

A host table might include all devices in a network organization. Each unique IP address can have a host name associated with it. The Cisco IOS software maintains a cache of host name-to-address mappings for use by EXEC commands. This cache speeds up the process of converting names to addresses.

Host names, unlike DNS names, are significant only on the router on which they are configured. The host table will allow the network administrator to type either the host name such as Auckland or the IP address to Telnet to a remote host.

The next page will explain how host tables are configured.

Configuration host tables 

3.2.7  This page will teach students how to configure a host table.

To assign host names to addresses, first enter global configuration mode. Issue the command ip host followed by the name of the destination and all IP addresses where the device can be reached. This maps the host name to each of its interface IP addresses. To test connectivity to the host, use a telnet or ping command with the name of the router or an IP address that is associated with the router name.

The procedure to configure a host table is as follows:

1. Enter global configuration mode.
2. Enter the ip host command followed by the name of the router and all IP addresses associated with the router interfaces.
3. Repeat Step 2 until all routers in the network are entered.
4. Save the configuration to NVRAM.

In the Lab Activities, students will configure host tables that identify routers and interfaces.

The next page explains how configuration files should be managed.
Configuration backup and Documentation

3.2.8 This page will discuss the backup and documentation of configuration files. 

The configuration of network devices determines how the network will behave. Management of device configuration includes the following tasks:

• List and compare configuration files on running devices.
• Store configuration files on network servers.
• Perform software installations and upgrades.

Configuration files should be stored as backup files in the event of a problem. Configuration files can be stored on a network server, on a TFTP server, or on a disk stored in a safe place. Include documentation with the offline information.