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Configuring a Device’s Unique Identity for the Network

 

To use a device in a network, you must configure the device’s identity. Doing this makes the device accessible on the network and so that other users can log in to it. You can refer to any Internet-connected machine in either of two ways:

  • By its IP address

  • By its hostname

Once you have a hostname, you can:

  • Find the IP address

  • Use the Domain Name System (DNS) to resolve an IP address from a hostname

  • Manually map the hostname to a static IP address

Although using DNS is an easier and more scalable way to resolve IP addresses from hostnames, you might not have a DNS entry for the router, or you might not want the computer to contact the DNS server to resolve a particular IP address. In this latter instance, perhaps you use this particular IP address frequently, or you might be using it only for testing or development purposes and do not want to give it a DNS entry.

To configure a router’s unique identity, you might need to include some or all of the following details: The hostname of the router, its IP address, the domain name, and IP addresses for two or three domain name servers.

Requirements

No special configuration beyond device initialization is required.

Overview

In this context, the hostname is the device’s name. It is easier for most people to remember a hostname than an IP address. Junos OS uses the configured hostname as part of the command prompt, to prepend log files and other accounting information, as well as in other places where knowing the device identity is useful. You can also use the hostname to telnet to a device.

The domain name is the string appended to hostnames that are not fully qualified. The domain name is the name of a network associated with an organization. For sites in the United States, domain names typically take the form of org-name.org-type—for example, “Juniper.net.”

In case your hostname and IP address do not have a DNS entry in a name server, configure a static mapping.

The values given in the following table are used to configure each of these variables. You need to substitute data specific to your device and network for these values.

Table 1: Values to Use in Example

Name of Variable

Value Used in Example

Value You Substitute

domain-name domain-name

domain-name device.example.net

host-name host-name

host-name example-re0

inet ip-address

inet 172.22.147.39

name-server ip-address

name-server 172.24.16.115

name-server 192.0.2.0

Configuration

CLI Quick Configuration

To quickly configure a device using this example

  • Copy the following commands and paste them in a text file

  • Remove any line breaks

  • Change the values listed here to match your network configuration

  • Copy and paste the commands into the CLI at the [edit] hierarchy level

  • Finally, enter commit from configuration mode

Configuring the Router’s Identity

Step-by-Step Procedure

To configure the identity settings of a device:

  1. Configure the domain name of your network.
  2. Configure the hostname, using the set system host-name command.
  3. Configure from one to three name servers.
  4. Map from the hostname to the IP address, using the set system static-host-mapping command.

Results

To check the configuration, use the configuration mode show system command.

When you have the correct configuration, enter commit.

Verification

Confirm the Device Hostname and IP Address

Purpose

Confirm the hostname and IP address of a device are as expected.

Action

Issue the show host host-name operational command.

user@example-re0> show host newton