I want to access my IIS hosted application over LAN. First I installed a DNS server. The DNS configuration steps are:

1. Go to DNS Manager -> right click on System Name -> click on configure a DNS Server.
2. DNS Server wizard open ->, click on next button -> Select radio button "forward lookup zone" click on next button.
3. In the second window. click on radio button "The server maintains the zone" and then click next.
4. Give the zone name "example.com"
5. Click on radio button, "Do Not allow dynamic updates". and then click next button.
6. In the next window, click on radio button "No it should not forward query" and then click next button.
7. Complete the configure a DNS server wizard and then click on finish button.

After it is managing the DNS records:

1. In DNS server wizard. open tree of forward lookup zone and right click on the new zone name "example.com" -> properties and click on "Start of authority" and write values on text boxes

   serial number=1
   primary server=systemname.domainname
   responsible person=hostmaster.domainname
   

2. Click on server name, highlight domain name, click on edit button and enter IP address of the server where I host my application.

3. Highlight new zone name and right click on it and click "New Host" option.

4. In this window there are three text boxes:

   Name(user parent name if blank)=scoring
   Fully Qualified Domain Name=scoring.example.com
   IP Address= My IP Address
   

   and check on "Create associated pointer(PTR) record" and click on "Add Host" Host button and then click done button.

I have host header for my application is "scoring" on port 80 and its working fine on server my application setting are I have change its,

Advance setting --> Application Pool Identity --> Local System

application can access on server with host name "scoring" but it can not access on machines on LAN.

When I change LAN machine host file that is under,

 C:/windows/system32/driver/etc/host 

and edit it and enter host name with hosted machine IP like this:

scoring 192.168.1.20

By making these changes I can run the application over LAN machines as I mentioned above DNS setting by which I can run App over LAN with out editing the client's host file.

What mistake am I doing in this configuration?