Distributing DNS load via DHCP

[Jeff Wieland]

We have a fairly large pool of address, and we'd like to distribute
the DNS load on this pool between two DNS servers.

Roughly, what I was thinking of doing is:

group {
    default-lease-time 21600;
    max-lease-time 28800;
    option domain-name "myuni.edu";
    option domain-name-servers 192.168.1.5, 192.168.1.6;

    subnet 192.168.128.0 netmask 255.255.240.0 {
        authoritative;
        option routers 192.168.128.1;
        # Select the DNS server order by examining the last bit of
        # the hardware address
        if (suffix(binary-to-ascii(2, 8, ":", hardware), 1) = "1") {
            option domain-name-servers 192.168.1.6, 192.168.1.5;
        } else {
            option domain-name-servers 192.168.1.5, 192.168.1.6;
        }

        pool {
            deny dynamic bootp clients;
            range 192.168.128.11 192.168.143.254;
        }
    }
}


Or would I be better off doing something with classes/subclasses?
I'm concerned about the performance impact of the if statement.

-- 
          Jeff Wieland            |         Purdue University
   Network Systems Administrator  |        ITN&S Data Networks
       Voice: (765)496-8234       |        155 S. Grant Street
        FAX: (765)494-6620        |   West Lafayette, IN 47907-2115