Check out: 10 Ways to Troubleshoot DNS Resolution Issues

In part 2, let’s look at DNS from a client perspective.

Take away

You should take away from this article the following:

- Use the ipconfig /all command to see your current DNS server, from a command line

- To see your DNS server information in Windows XP, go to Start à Settings à Network Connections à Local Area Connection. Click on the Support Tab, then click on Details.

- To clear your local host DNS cache, from the command line, do ipconfig /flushdns

The best way to learn about DNS is to setup your own lab with a lab guide from Train Signal and follow their video instruction. Click here to see their site.

Most of us work more on a client each day than a server so it makes sense to begin learning about DNS on a client. Do you know how to find your current DNS server IP address? Let’s walk through doing this with both the command line and the graphical interface.

Windows command-line

To find your DNS server IP address (or addresses) at the command line, open a command prompt by going to Start à Run, then typing cmd, and pressing enter. You will see a black window come up that is really a DOS-like interface. At that command prompt, type ipconfig /all. You will see output that looks like this:

Windows graphical interface

To find your DNS server IP address (or addresses) in the Windows graphical interface, go to Start à Settings à Network Connections à Local Area Connection. Click on the Support Tab, then click on Details. Your window will look like this:

Sometimes, your PC may have an out of date DNS entry to remedy this, you need to clear your DNS cache on the PC. That cache is where frequently used DNS name to IP address mappings are stored. To flush (clear) this cache, type ipconfig /flushdns at the windows command prompt.

For some excellent video training on DNS and hands-on labs, visit Trainsignal.com’s website.

Part 3 is coming soon…

Take away

You should take away from this article that DNS is a critical part of every organization’s infrastructure. It maps hostnames to IP addresses and IP addresses back to hostnames. The best way to learn about DNS is to setup your own lab with a lab guide from Train Signal and follow their video instruction. Click here to see a course listing.

DNS stands for Domain Name System. There are many RFC standards that define how DNS functions. Windows DNS server is built into all versions of Windows Server operating system.

The purpose of DNS is to map a hostname (like www.trainsignal.com) to an IP address like 10.10.10.10. For any device to talk to another device, each device must know the other device’s IP address. Most users don’t know the IP address of the server they want to talk to, thus, they type in the name of the host and their computer contacts a DNS server via that server’s IP address (usually defined by DHCP). That DNS server may have to go to another server to find out the IP address of the original hostname that the user’s PC requests. Once the DNS server has the IP address, it returns that IP address to the computer that requested it. That computer then uses the IP address to contact the server.

So, as you can imagine, without a working DNS server that your computer can contact, it may seem like the whole network is down. That is because you are contacting almost every resource on the network using names instead of IP addresses.

For some excellent video training on DNS and hands-on labs, visit Trainsignal.com’s website for a free DNS instructional video demo.

Learn more in Part 2…