Slow Loading Websites & Resources
DNS (Domain Name System) is a service that translates website & computer names to ips (i.e., Internet Protocol addresses) so you can use friendly domain names like Google.com & Randy-laptop.
On a Windows domain this service is handled by the DC (Domain Controller).
IPs – IPv4
Note that every device on your network should have a unique ip. A duplicate ip causes confusion. Only the 1st device to secure an ip will be able to access the network.
Likewise many websites have a unique ip but this is not always the case. If your test website uses HTTP Secure(e,g, https://www.google.com) then it has a unique website.
IPv4 is the easier protocol to deal with when accessing resources.
This article specifically applies to a Server 2008 R2 Standard single server domain with AD (Active Directory) but the principles can be applied to DNS servers everywhere.
A Server 2008 R2 Standard single server domain should point only to itself for DNS and not an external server. The rest of the domain should also point to this server. There should be no reason to have a forwarder in a single server domain but you might run across one if a server has been removed somehow.
Troubleshooting Domain DNS
If your clients on the domain access computer resources like network shares & websites without issues then your DNS is working properly. If on the other hand it takes a long time for a website or network share to load then you may want to investigate DNS.
A simple way to troubleshoot DNS is to try accessing the ip rather than the FQDN (Fully Qualified Domain Name). Chances are you don’t know the ip of the resource but you can ping it from a CMD prompt.
The examples below we are pinging FQDN cisco.com & Randy-laptop with the -4 flag set (return IPv4). Once we have the ip we can try accessing these resources.
In the case of cisco.com we put the ip 184.108.40.206 in our browser. If the page loads for the ip and not the FQDN then we have a DNS problem.
In the case of the network resource, we can try connecting with a net use command. Assuming you have permission to access the save share on Randy-laptop then the net use command should connect drive X. If you can access the share via ip but not FQDN then we have issues with DNS.
C:\Users\Randy>ping cisco.com -4
Pinging cisco.com [220.127.116.11] with 32 bytes of data:
C:\Users\Randy>ping Randy-laptop -4
Pinging Randy-Laptop [192.168.1.25] with 32 bytes of data:
Connecting to network share using ip:
C:\Users\Randy>net use x: \\192.168.1.25\save
The command completed successfully.
DNS Problem Forwarder
In our example we are going to assume that the network is slow and resources drag. Troubleshooting leads us to believe there is a DNS problem. Looking at the properties of our DNS we find a forwarder.
We know the forwarder should not be there so we remove it & restart the DNS service. This is more likely to occur when you remove a DNS server from your domain. It can also occur when you move your DC to a new domain leaving the old DNS server behind.