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.

Login banners / Configuring message-of-the-day (MOTD)

Login banners

3.2.4 This page will explain what login banners are and why they are used.

A login banner is a message that is displayed at login. Login banners can be used to convey messages that affect all network users, such as scheduled system shutdowns.

Login banners can be seen by anyone. Therefore, a banner message should be worded carefully. “Welcome” is an invitation for anyone to enter a router and is probably not an appropriate message.

A login banner should warn users not to attempt login unless they are authorized. A message such as “This is a secure system, authorized access only!” informs unwanted visitors that any further intrusion is illegal.

The next page will explain how message-of-the-day banners are configured.

Configuring message-of-the-day (MOTD)

3.2.5 This page will explain how a message-of-the-day (MOTD) banner can be configured and displayed on all connected terminals. 

Enter global configuration mode to configure an MOTD banner. Use the banner motd command, followed by a space and a delimiting character, such as the pound sign (#). Add an MOTD followed by a space and the delimiting character again.

Follow these steps to create and display a message-of-the-day:

1. Use the configure terminal command to enter global configuration mode.
2. Enter the command banner motd # <message of the day > # .
3. Issue the copy running-config startup-config command to save the changes.

Students can use the Lab Activities to configure basic router settings such as the MOTD.

The next page will discuss host name resolution. 
 

Configuring an interface description

Configuring an interface description
3.2.3 This page will teach students how to configure an interface description.


To configure an interface description, enter global configuration mode. From global configuration mode, enter interface configuration mode. Use the command description followed by the information.

The steps to configure an interface description are as follows:

1. Use the configure terminal command to enter global configuration mode.
2. Enter a specific interface mode such as interface ethernet 0.
3. Enter the command description followed by the information that is to be displayed, such as XYZ Network, Building 18.
4. Use Ctrl-Z to exit interface mode and return to privileged EXEC mode.
5. Use the copy running-config startup-config command to save the configuration changes to NVRAM.

Here are two examples of interface descriptions:

interface ethernet 0
description LAN Engineering, Bldg.2
interface serial 0
description ABC network 1, Circuit 1

The next page will describe login banners.

Interface descriptions

Interface descriptions
3.2.2 This page will explain what interface descriptions are and why they are used.


An interface description should identify important information such as a router, a circuit number, or a specific network segment. A description of an interface can help a network user remember specific information about the interface, such as what network the interface services.

The description will appear in the configuration files that exist in the router memory. However, it will not affect the operation of a router. A description only provides information about an interface. Descriptions are created by following a standard format that applies to each interface. The description may include the purpose and location of the interface, other devices or locations connected to the interface, and circuit identifiers. Descriptions allow support personnel to better understand the scope of problems related to an interface and allow for faster resolution of problems.

The next page will describe how interface descriptions are configured.

Importance of configuration standards

Importance of configuration standards
3.2.1 This page explains why it is important to develop standards for configuration files within an organization.


Configuration standards can be used to control of the number of configuration files that must be maintained, how the files are stored, and where the files are stored.

A standard is a set of rules or procedures that are either widely used or officially specified. If an organization does not have standards, the network will be in chaos if a service interruption occurs.

Network management requires a centralized support standard. Configuration, security, performance, and other issues must be addressed for the network to function properly. The creation of standards for network consistency helps reduce network complexity, unplanned downtime, and events that may affect network performance.

The next page will discuss interface descriptions.

Configuring an Ethernet interface

Configuring an Ethernet interface
3.1.7 This page will explain how an Ethernet interface can be configured from the console or a virtual terminal line.


Each Ethernet interface must have an IP address and subnet mask to route IP packets.

To configure an Ethernet interface follow these steps:

1. Enter global configuration mode.
2. Enter interface configuration mode.
3. Specify the interface address and subnet mask.
4. Enable the interface.

By default, interfaces are turned off, or disabled. To turn on or enable an interface, the command no shutdown is entered. If an interface needs to be disabled for maintenance or troubleshooting, use the shutdown command to turn off the interface.

This page concludes this lesson. The next lesson will explain how a configuration is finalized. The first page covers the importance of configuration standards.

Configuring an Ethernet interface

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