KanREN DHCP Seminar November 7-9, 2005

Configuring Client Options

The ISC server specifies optional information to pass to the client using the option <option-name> <option-value> syntax. A list of supported options is available in Appendix D of The DHCP Handbook by Droms and Lemon, and in the Unix man page for dhcp-options.

Two options are already in use in the classroom configuration—the DNS domain name and DNS nameserver list:

# Define domain name and nameservers for entire lab.

option domain-name "kanren.net";

option domain-name-servers 164.113.130.1, 164.113.207.250,

164.113.92.251, 164.113.31.235;

Unfortunately, there are very few other options that are easy to demonstrate without additional infrastructure that's not available here. For the sake of an example, configure a NETBIOS (WINS) nameserver to send to your client. Add the following to your main configuration file in the global section:

# Pass a NETBIOS nameserver option to the client.

option netbios-name-servers 192.168.10.253;

Test your configuration, then activate your changes.

lab1:/var/dhcp # dhcpd -t

Internet Systems Consortium DHCP Server V3.0.4b2

Copyright 2004-2005 Internet Systems Consortium.

All rights reserved.

For info, please visit http://www.isc.org/sw/dhcp/

lab1:/var/dhcp # kill `cat dhcpd.pid`

lab1:/var/dhcp # dhcpd

If you renew the lease on your client, it should receive the new setting. I'm not sure whether there's a way to view that on a Mac, but on a Windows machine, you should see it as one of the entries under ipconfig /all .

2005-11-07T09:22:35