DNS is short for the Domain Name Server or in non-technical terms the PHONE BOOK OF THE INTERNET.  You type in a web site name and the DNS server gives your computer the phone number (aka ip address). But you say, "My DNS is working just fine. Why should I care about this?". Very simple, would you trust a criminal to give you the right phone number? I didn't think so. There are security concerns with simply accepting the DNS server that is provided by your Internet connection, especially the untrusted "coffee shop" wifi.

I am not saying all DNS servers are bad, but there is a simple change you can make to ensure you always get good DNS look-ups. OpenDNS is my favorite as they provide several features like phishing protection, typo correction, and optional content filtering.  OpenDNS works independently of your ISP and therefore can be set as a fixed DNS address on your workstation and of course it is FREE.

For information on a current plague affecting some DNS servers, please see the following article:

http://www.theregister.co.uk/2008/12/05/new_dnschanger_hijacks/

Of course, the folks over at OpenDNS have long known about those problems and their service is not affected by these problems.

For XP users:

Simply open the Control Panel (classic view). Select Network Connections, select your network card or wireless card and go to File / Properties. Scroll down to "Internet Protocol TCP/IP" and click the properties button. Select "Use the following DNS server addresses" and type in 208.67.222.222 in the first line and 208.67.220.220 in the second. Click OK the Click Close.

For MAC users:

Open the Preferences panel. (Apple menu / System preferences). Select Network. Click on Advanced. Click on the DNS tab. Press the + to add a new address and type in 208.67.222.222. Repeat the + and type in 208.67.220.220. Also make sure your router is setup with OpenDNS (see below).

Congratulations, you have now switched to a fast and secure DNS server. To check this, open your web browser and type in a bad URL like "123.abc". The OpenDNS guide page should appear helping you find the correct page. If you do not see the OpenDNS guide, you might need to reboot.

You can also update your router to give hand out the OpenDNS servers. Login to your router via your web browser. Linksys users type in 192.168.1.1 or D-Link users 192.168.0.1 and type in the 208.67.222.222 and 208.67.220.220 in the DNS fields in the LAN or DHCP pages.

It is important to note however if you take your laptop places, you really should use the OpenDNS numbers in your TCP/IP preferences, as you will be subject to their DNS servers when you are not by your own safe router.