Return DNS replies to specific clients

I'm trying to return DNS replies to only a couple of different subnets. If the request comes in from anything else, I'd like to ignore it, or return a bogus response. Trying to get this to work, but I'm sure I'm doing something wrong.

 

 

when DNS_REQUEST {

 

if { [IP::addr [IP::client_addr]/24 equals 10.0.0.0/24] or \

 

[IP::addr [IP::client_addr]/24 equals 192.168.76.0/24]

 

} {

 

pool Good_Pool

 

} else {

 

pool Dead_Pool }

 

}