I have a need to write a DNS Proxy that will choose which server to send a query to based on info in a DB at the time of the query. I can write the code that determines if the info I am looking for is in the database. What I want is to determine the querying IP, look to see if there is an entry in the DB for it, and send the query to NS:5353 if it is, and NS:5300 if it isn't. The info for the IP can expire, thus changing the response. This means changing the TTL on the responses coming back. What's a good place to get the info I need to parse the originating DNS query, and modify the response?