In a Hurry?
  Go straight to the Quick Selection Guide for short detailed summaries of each product

  Go straight to the Change Log to see what's new since June 2011


Want to change your DNS server? You might need to know more about What DNS Servers Do or you might need to know How to Find the Best DNS Server.

There are three sections in this how to guide.

  1. Why change my DNS Server?
  2. How is your system configured for DNS
  3. How to change your DNS settings

For speedy performance

Every web page requires an IP address before it can be loaded. The time taken to resolve a DNS name can add several seconds to the loading of a page. The faster your DNS server then the quicker your pages will load.

The larger the database of the DNS server then the greater the likelihood that the name will be found without searching on other DNS servers. These cached hits are much faster than uncached hits. Typically by a factor of ten so a 0.1 second.cached name could take 1 second if it is not found in the DNS server database.

For increased reliabilty

Most DNS servers are available near enough to 100% of the time. If your isn't then find a more reliable server. DNS queries can timeout or, in the worst case, receive no response at all. There are several ways to reduce such problems:

  • Your primary DNS server should be the fastest DNS server for you.
  • Define more than one DNS server to use - a minimum of two and probably more - to reduce the risk of one or more DNS servers not being available.
  • Use DNS servers that are in different cities or countries, ie geographically diverse, to reduce the likelihood that one 'disaster' will affect all your DNS servers at the same time.
  • Have at least one DNS server that is close to your location, probably a DNS server at your Internet Service Provider (ISP).
  • If your ISP is small then definitely look for a DNS server with a larger database.

For greater safety

All DNS servers do not offer the same features or have the same vulnerabilities. Many DNS servers still do not operate using established security features like DNSSEC.

Some DNS servers provide additional features such as the filtering of web addresses to improve security. These solutions can create other problems.:

  • Malware protection is provided by Norton DNS and others
  • Phishing protection is provided by OpenDNS and others
  • Category filtering for parental controls is provided by OpenDNS and others


Automatic configuration from your ISP?

You will usually define your DNS servers when you configure your Internet network connection whether dial-up or broadband. Most Internet Service Providers (ISPs) have automatic configuration of some sort so the DNS servers are defined automatically. If you had to manually configure the network connection then chances are that you also had to manually define the DNS servers.

Configuration on your system

DNS servers settings will exist for each PC you use on the Internet whether they were manually input or automatically configured. The key question is where are my external DNS servers defined?

  • At your PC? If it is directly connected to a modem for Internet access then it will have the system DNS servers.
  • At your router? If you have a local area network (LAN) then a router is usually the best place to define your DNS servers. Any device connected to that router can be updated automatically using the Dynamic Host Configuration Protocol (DHCP). This means that changing the external DNS servers at the router will affect all devices connecting to it using DHCP.
    The problem with this is that cheap home routers can cause problems. This seems to be the case with my router. I have more problems when my router is configured as the DNS Server with the IP address192.168.2.1 (an address reserved for internal networks) than if I define the DNS servers manually at each PC.

How to find your system DNS server configuration

There are several methods to find your system's DNS server configuration.

  • I recommend that you use the excellent resources for changing your DNS configuration in the next section. The best cover most operating systems and many routers.
  • In your network connection settings, go to the properties for your network connection, select the network card if there is more than one, and then the TCP/IP protocal properties which include the DNS servers. If you are using Windows 95, 98 or Millenium then you can run winipcfg.exe.
  • The programs described in How to Find the Best DNS Server will tell you what your DNS servers are.
  • At the Windows command line enter ipconfig /all to display the system IP configuration including the system DNS servers. For Windows 2000 and later there are two ways to get the Windows command prompt:
    • Go to the start menu; select "Run"; enter "CMD".
    • Go to the start menu; select All Programs; select Accessories; on some systems select "System Tools"; select "Command prompt".

Example: Inspect your network connection settings in Windows

Note that you can exit out of this by pressing the Esc key, selecting Cancel, or closing each window.

  • Find the network connection icon in the system tray at the bottom right of your screen.
    Right click on the network connection icon with your mouse to bring up the context menu.
    Select the 'Status' menu item.

    Open the network connection from the system tray

  • The Local Area Connection Status dialog should display.
    Select the 'Properties' button.

Open the Local Area Connection Status dialog


  • The Local Area Connection Properties dialog should display.
    Select 'Internet Protocol TCP/IP'

Open the Local Area Connection Properties dialog

  • The Internet Protocol (TCP/IP) Properties dialog should display.
    The DNS configuration is visible at the bottom.
    In this example, the DNS servers have been defined manually but they would not be visible if the radio button was selected for 'Obtain DNS server address automatically'.
    If they are visible, select the 'Advanced' button to see the Advanced TCP/IP Settings where we can see if more than two DNS servers are defined.Open the Internet Protocol (TCP/IP) Properties dialog
  • The Advanced TCP/IP Settings dialog should display.
    The IP Settings tab will be displayed first.
    Select the 'DNS' tab to display the DNS server addresses. In this example, there are only two DNS servers.
    I have also selected the 'Add' button to bring up the 'TCP/IP DNS Server' dialog in which I've entered a DNS server IP address ready to 'Add'.
    The sort order can be changed using the arrows at the right..Open the Advanced TCP/IP Settings dialog

How to test if the system DNS configuration is damaged

For further troubleshooting of any sort of network problem including DNS you should look at your system first. You can incorrectly configure your system DNS by, for example, typing in incorrect IP addresses for the DNS servers. If you do this then your web browser will not be able to access Internet resources using domain names but you should be able to use URLs with a valid IP address. Just type a valid IP address in as the URL and your browser should add the rest e.g. is converted to

If you find you have lost all web access even using IP addresses then that is very unlikely to be a DNS problem. Your network connection could be down or malware could have changed your configuration (e.g. by setting your network connection to use a proxy server).

Here's a list of some things that you can do:

  • If you haven't already done so, check your network configuration.
  • Flushing your system's DNS cache can fix some problems.
  • Use command line utilities:
    • NSLOOKUP will confirm the DNS server is working and correctly resolving queries
    • TRACERT (traceroute) traces the network path taken to resolve a name. It can indicate whether the problem is occurring on your network, the destination network or somewhere in between.
Despite being widely recommended, the PING command line utility has limited use for DNS resolution — the "-A" option can find the domain name for an IP address. Typically, you PING an IP address to find out if it if you can communicate with it. You will find that pinging a DNS server may timeout, indicating that you cannot communicate with it, even if the DNS server is fully functioning. This happens because the DNS server is configured to ignore PING requests (ICMP packets). This security measure prevents a couple of denial-of-service attacks.

Before configuring your chosen DNS Servers

You might want to run a DNS Spoof Test to check the vulnerability of your chosen DNS servers. Just be aware that some routers lockup or crash if you run these tests. GRC provides a list of routers with known problems. It didn't include mine which crashed when I tested it. I had guessed it might because it is similar to some of those listed. That's a good reason to get a better router. See GRC's notes at the bottom of the DNS Spoof Test page for a list of routers that fail in this way.

Resources to help you change your DNS configuration

There are programs to automate the changeover to better DNS servers but I'd give them all a miss. Instead, I encourage you to visit some excellent resources that will help you.

Web quides and tutorials

If you are at all unsure, you should have a look at these resources about configuring your DNS servers. Just remember that the DNS server IP addresses they show you in the guides are for their servers. You can substitute the IP addresses for your preferred DNS servers.

Software that might help you to change your configuration but are too limited

DNS Jumper will change your DNS addresses for you but has some significant weaknesses:

  • Only the first two DNS servers can be changed on your system. If you want more than two then you will need to find another solution.
  • By default it only includes public DNS servers in its database. You can add others.
  • It can only change to a set of DNS servers e.g. both from Google or both from OpenDNS. If you want to mix service providers then you will have to add a new set yourself.

DNS Helper (formerly Google DNS Helper) is a utility to change to one of the main global DNS service providers that I do not recommend:

  • You cannot add your own servers apart from one set of custom DNS servers.
  • If you change DNS servers while in a Windows session it will not update the DNS server IPs to restore until you start a new session.

Public DNS Server Tool is too limited to be recommended.

After you change your DNS configuration

Flush the system DNS caches

When you change your DNS configuration you should clear the system caches so that the new DNS settings take immediate effect. I use CCleaner, the Editor's Choice for Best Free File Cleaner, to clear the caches because it runs once and cleans each browser's cache. Other options are more limited.

  • Flush the system DNS resolver cache.
    The Windows command ipconfig /flushdns will flush the DNS resolver cache and refresh it with only the entries in the Hosts file. ipconfig /displaydns will display the system DNS cache.
  • Flush your web browser caches
    Some browsers will allow you to do this from the menu.
Related Products and Links

Using DNS servers for security

Products mentioned here

Quick Selection Guide

DNS Jumper    Rating 5 of 10

Pros   quick test of DNS servers; changes DNS server for one network interface card (NIC); multi-language
Cons   cannot mix DNS servers from different providers unless you create a new DNS server entry
Developer Home Page
Download link
File Size   0.5 MB  Version 1.04  License Type Unrestricted Freeware  Installation Requirements Windows XP, Vista, 7
Portable   Portable software    64 Bit version available 64 bit Windows support
Languages   Arabic, Chinese, Dutch, English, French, German, Greek, Hungarian, Indonesian, Italienisch, Japanese, Portuguese (Brazil), Romanian, Russian, Spanish, Swedish, Turkish, Vietnamese

DNS Helper    Rating 2 of 10

Pros   changes DNS server to one of several global service providers
Cons   too limited; doesn't identify network interface cards (NIC)
Developer Home Page
The developer's home page has a bad WOT rating so I have provided this link instead.
Download link
File Size   0.1 MB  Version 1.0  License Type Unrestricted Freeware  Installation Requirements Windows XP, Vista, 7 - requires Microsoft .Net Framework 2.0
Portable   Portable software    64 Bit version available 64 bit Windows support

Public DNS Server Tool    Rating 2 of 10

Pros   changes DNS server for any network interface card (NIC)
Cons   limited list of public DNS servers; didn't identify the system DNS servers; cannot input additional DNS servers; no DNS server speed test
Developer Home Page
Download link
File Size   0.2 MB Version 0.91   License Type Unrestricted Freeware  Installation Requirements Windows XP, Vista, 7
Portable   Portable software     64 Bit version available 64 bit Windows XP support



This software category is maintained by volunteer editor Remah.

  "I've used TechSupportAlert and the older Support Alert Newsletter for almost a decade so I have saved hundreds of hours of work and many more dollars by following Gizmo's Freeware recommendations. Thanks for the opportunity to give something back."  

If you have had a similar experience then you should consider becoming a reviewer too.

Change Log




July 2011 Removed the sections about DNS into the article What DNS Servers Do Remah

June 2011

New article



Domain Name System, DNS, DNS server, DNS resolver, DNS resolution, DNS name server, Internet name server, DNS Helper, Public DNS Server Tool, DNS Jumper

Back to the top of the article.


Please rate this article: 

Your rating: None
No votes yet