Randomize DNS servers

[Simon Hobson]

Tim Gavin wrote:
>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.

>I should have mentioned, these are in two big IP blocks, and I'm
>merging them into one.  They're set up as a /21 and a /22.

So in fact, you don't need them 'random', just distributed.

You could do this :

subnet blah blah
   pool {
     range 10.0.0.10 10.0.0.254 ;
     option dns-servers (dns1; dns2) ;
   {
   pool {
     range 10.0.1.1 10.0.1.254 ;
     option dns-servers (dns2; dns3) ;
   {
   pool {
     range 10.0.2.1 10.0.2.254 ;
     option dns-servers (dns3; dns1) ;
   {
}

Each client will get a specific and fixed set of DNS servers, but 
overall the effect will look random assuming you've got clients 
spread reasonably randomly across your IP range.

-- 
Simon Hobson

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