DHCPv4 Client Host Names

By default, the DHCPv4 client does not supply its own host name, because the client expects the DHCP server to supply the host name. The DHCPv4 server is configured to supply host names to DHCPv4 clients by default. When you use the DHCPv4 client and server together, these defaults work well. However, when you use the DHCPv4 client with some third-party DHCP servers, the client might not receive a host name from the server. If the DHCP client does not receive a host name through DHCP, the client system looks at the /etc/nodename file for a name to use as the host name. If the file is empty, the host name is set to unknown.

If the DHCP server supplies a name in the DHCP Hostname option, the client uses that host name, even if a different value is placed in the /etc/nodename file. If you want the client to use a specific host name, you can enable the client to request that name. See the following procedure.

Note - The following procedure does not work with all DHCP servers. Through this procedure you are requiring the client to send a specific host name to the DHCP server, and to expect the same name in return.

However, the DHCP server does not have to respect this request and many do not. They simply return a different name.

How to Enable a DHCPv4 Client to Request a Specific Host Name

On the client system, edit the /etc/default/dhcpagent file as superuser.
Find the REQUEST_HOSTNAME keyword in the /etc/default/dhcpagent file and modify the keyword as follows:
```
REQUEST_HOSTNAME=yes
```
If a comment sign (#) is in front of REQUEST_HOSTNAME, remove the #. If the REQUEST_HOSTNAME keyword is not present, insert the keyword.
Edit the /etc/hostname.interface file on the client system to add the following line:inet hostname
hostname is the name that you want the client to use.
Type the following commands to have the client perform a full DHCP negotiation upon rebooting:
```
# ifconfig interface dhcp release
# reboot
```
The DHCP data that is cached on the client is removed. The client restarts the protocol to request new configuration information, including a new host name. The DHCP server first makes sure that the host name is not in use by another system on the network. The server then assigns the host name to the client. If configured to do so, the DHCP server can update name services with the client's host name.
If you want to change the host name later, repeat Step 3 and Step 4.

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	System Administration Guide: IP Services Oracle Solaris 10 8/11 Information Library