Match randomized letter casing in query name (DNS0X20)
Enabling this option helps protect against DNS spoofing attacks. See How to secure your server / DNS spoofing.
This is only an option because some older DNS servers/forwarders may respond incorrectly (rare) or not respond at all (very rare) to these requests (randomized letter casing in query name).
Simple DNS Plus is able to correct for cases where an incorrect response is provided (query name letter casing mismatch or error code) - this just takes a few extra requests causing a small delay and a bit more network traffic.
However, in cases where no response is provided, Simple DNS Plus will not be able to resolve the query. As mentioned, this is very rare, and we highly recommend enabling this option.