Prevent Clients with Multiple NICs from Getting Multiple DHCP Addresses
Posted on 2010-09-07
I have dhcpd and bind 9 running on CentOS, serving addresses to several subnets. Some of the clients obtaining ip address leases have LAN and Wireless connections, and thus grab two IP addresses. I think the server versions are irrelevant, but dhcpd is 3.0.5 bind is 9.3.6, CentOS is 5.5. Clients are Windows XP Pro SP3 or Windows 7.
I would like to limit each host to a single IP address for the following reasons: first, it's just a waste of the address pool, though that is not my primary motivation. Secondly, and more importantly for our organization, when a client has two addresses (one per interface) and one of those interfaces goes away (e.g., the network cable gets unplugged, or the user moves out of Wireless range) then one of the two addresses becomes useless. A DDNS update does not occur in this case, making it impossible for us (tech support) to access such a host via the hostname and DNS lookup.
Over time, the DDNS updates seem to make a mess out of DNS.
So, can I prevent a host from getting more than one IP address? All clients have client-hostnames, and I would prefer a server-side solution.