I have a couple of questions I think mine is a bit different from the other thread.
My Nameservers and Website are hosted on the same box.

Right now I have a win server hosting a website with NS1 and NS2 on the same box.

I have a second server box and I was wondering if I created an NS3, NS4 on that box with a backup of the website if the main server goes down with NS1, NS2 does that mean that people trying to get to my .com domain will automatically be sent to the second box with NS3, NS4 without seeing any outage ?

I'm trying to just have a backup in place to avoid downtime if my main server has any hardware failure.

Thanks for any info,

No!

First of all, having ns1/ns2 hosted on the same box is a hack as you need at least two nameservers assigned to a domain and having both nameservers on the same box saves having to run two boxes. If you do have two boxes, you should have ns1 pointing at the first box and ns2 at the second. You will gain nothing by having ns1/2 on one box and ns3/4 on the second.

When a client looks up your domain to get an IP, a random nameserver is used, which tries to ensure that each name server has pretty much the same load. If you have two boxes, they will need different IPs, so if you have your A record on ns1/2 pointing to box 1 and ns3/4 pointing at box 2, your clients will be directed to each box 50% of the time. If one box goes down, your clients will get an error half the time.

In order to get true redundency in case one of your servers goes down, you need two (or more) servers with the content synched in some way, with a load balancer. Then, if one box goes down, the load balancer will direct all the traffic to the other. Otherwise, the load balance will... balance the load between the two boxes.

Hope this makes sense!

Alright, well thanks for people's replies. It looks like it would be more complicated than I expected.

i have been doing some research for the past week on this and hope this helps .

if you have ns1. on one server and ns2. on another server. two different ips -- both having there own dns server enabled . if server ns1. goes down then the traffic will be sent to server ns2. but keep in mind some of your user may stil lbe directed to ns1. at random and see that the server is offline .

a hack for this is ; update the dns A record on server ns2. once server ns1. goes offline . so all traffic will go directly to the backup server. to accomplish this you have to have a very low TTL within both dns records . i have not found a way to auto this task of updating the a record on server number 2 .

another expensive option was to go with SM load balancer option that comes with failover for 49.99 a month . wow heheheh for first option is called "round robin " do some googling to see what that means . i am thinking about working on a script that will check the status of server number 1 and if status = null then update dns record on server number 2 -- sound easy huh