Dns forwarders not validating
This decreases the Internet traffic over the network and improves the response time for DNS clients.
However, having said that, you may want to have at least 2 working DNS servers acting as forwarders because if one fails you will still have name resolution.
You want to have more than one DNS server for obvious redundancy purposes.
When you have two or more DNS servers, you can configure one of them, some of them, or all of them to use forwarders.
Another reason for my recommendation is related with firewall configuration.
So...let's say I set up DNS forwarders in a Windows DNS server and then query using nslookup (or something else? Can I actually see where the Windows DNS server is querying its forwarder, which forwarder it ended up using, and the response from that forwarder?