Randomize DNS servers

[John Hascall]

> I have several DNS servers that are lower performance than I would
> like.  Until such time as I can afford to replace them, is there a way
> in DNS (serving around 2000 clients) that I can assign a group of DNS
> servers, and assign them randomly?  I.E., one user gets DNS1 & DNS2,
> another clent gets DNS3 & DNS1, and the next gets DNS3 & DNS2.

Assuming you are serving multiple subnets, you can include
an 'option domain-name-servers ...' statement in each subnet:

        subnet 10.10.199.128 netmask 255.255.255.224 {
                ...
                option domain-name-servers
                        129.186.1.200, 129.186.78.200, 129.186.140.200;
        }
        subnet 129.186.199.128 netmask 255.255.255.224 {
                ...
                option domain-name-servers
                        129.186.142.200, 129.186.140.200, 129.186.1.200;
        }

In our case, our config file is built by software from a database,
so we can easily have the order randomized, but you could certainly
do it by hand if that's how you make your config file.

John