We had one of our nameservers go down yesterday and everyone in the office was scratching their heads wondering why our other DNS didn't pick up the load in a timely manner (if at all). The two nameservers are not in master-slave configuration, but their zones and records in the zones are all identical. It should be noted that the two nameservers live on two completely different networks (Comcast and Verizon) as well.
I theorized that because we only had one NS entry in each zone file, no resolver would ever see the secondary nameserver -- and was looked at is if I had two heads. We have one entry in each zone (on each nameserver), ns1.xxxxx.com. So my question is: am I right in thinking that whatever resolver -- whether it be a Windows machine or a mobile device -- will not know about our secondary nameserver, ns2.xxxxx.com, unless we explicitly put an NS entry for that server into each zone file?
I am a programmer primarily, and am now being introduced to DNS, so I want to make sure that I have the right idea of things before bringing my idea to the table as a solution again. I certainly do see many people all over Google having multiple NS entries -- sometimes up to 4 -- in a zone file for any given website.
Thanks for any help, folks.