How to Fix “default server unknown nslookup”

Nslookup Nslookup

Hello everybody, today I’m going to teach you how to fix a very common problem. When you have established a new Domain Controller, by default, you will get an error notification when you try running  “NSLOOKUP” from any computer in your domain,. I’m sure many of you have experienced this. It happens because you have not created a Reverse Lookup Zone (PTR record).

As described in my old article  (DNS records explanation) in order to work with NSLOOKUP and get all the correct queries and information, you should create the PTR record and point it to your DC.

The Error is:

Default Server unknown

and IP :1:


Default server unknown nslookup

Go to “Reverse Lookup Zone ” and Create new Zone:

Default server unknown nslookup

Allow “Primary Zone and Store the Zone in AD” and proceed:

Default server unknown nslookup


Default server unknown nslookup

Allow “IPv4 Reverse Lookup Zone“:


You have to type your ID Network (Subnet):


Allow Dynamic Updates (Automatically DNS records registration):



Default server unknown nslookup

If your DC didn’t create the PTR record, please go to “Reverse Lookup Zone” and create the record manually with the following steps:


Select your DC’s record

Default server unknown nslookup


Another way to create this record is

Allow PTR record of DC’s record through your zone:

Default server unknown nslookup


Alright, so the purpose of this article was to show you how to fix the “Default server unknown nslookup” issue but we also alloweded automatic PTR registration on our DNS, the next NSLOOK you run will be like this:


Default server unknown nslookup

  1. Ayyappa 3 years ago

    Thanks for your support

  2. Emil Gitman 3 years ago

    Hi Meir. Good Guide. Solved my problem in 30 seconds. Thanks

  3. Deden 2 years ago

    Dear Sir,
    I have same problem,
    can you gimme solution or anything will I can try to do
    1. already have folder reverse and have checked in ptr record
    but the output still same,
    2. I have 3 dc, 2 dc in same network, 1 dc in other branch, is this mean a network issues?
    in forward lookup zones have errors and its show “Zone not loaded by dns server”

    can you help
    thanks in advance

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