We have setup NPM and have added a few subnets for the discovery process. Is there a way to give a large range of IPs like a class B and list the subnets to be excluded?
There is no way to exclude specific subnets from from a larger subnet in the Discovery Tool. It would be a nice feature though.
Your best bet is to enter the largest subnet (or seed routers) you can and add additional smaller ones to achieve your goal.