We have a sub domain in our dns tree for a GTM. within the GTM (sub domain ) we have three name servers listed. The question is that is there some kind of time out if the first server in the name server tab does not reply with an answer? From the firewall engineers perspective they are saying that it seems like the DC only tried the third NS in the list? What would cause it to get stuck on on NS(not that i think this is the problem) and how does it decide which record to use and when to switch?