Linux Community Magazine

DNS is the Domain Name System, an internet task force that allows the computer to register to domain names, or as we mostly know them online resources. Once you type the address of a website and actually visit it, your computer will store the DNS information this happens only the first time that you visit every website. All the subsequent times that you will visit the particular website, the computer will search for the so called DNS cache, which defines the information stored from the previous time. Once the information is located, the computer is ready to use it, instead of registering all over again. This allows the exchange of DNS information to be faster and the DNS resolution easier.

Every address is stored for a day 24 hours. If the IP of the particular website changes for any reason within these 24 hours, then the DNS cache will give you an error message and will inform you that it cannot connect you to the website you want.

Even the slightest change in the stored information can cause some issues. This is where flushing DNS comes to the game. Although few users know how to flush DNS, it is an action of significant importance, because it can resolve cache and help it locate the pertinent DNS information for the particular website. The DNS cache cannot recognise problematic entries and can store everything, causing malfunctions later on; this can prohibit your connection to the website you want. Knowing how to flush DNS can help you restore the positive information and help your computer connect to any page.

How to Flush DNS if you have Windows XP or Vista?

The first thing you need to do is to use the ipconfig /flushdns command. Type C:>ipconfig /flushdns and you will manage to configure IP and flush the Resolver Cache.

What can you do if you have a Mac?

If your operating system is Mac OSX Leopard, you can type the command bash-2.05a$ dnscacheutil -flushcache

If your operating system is OSX and older, then you can perform this task typing bash-2.05a$ lookupd -flushcache

If you are working on Linux, then you can use the nscd demon to manage the problem: you need to restart the demon, using the command `/etc/init.d/nscd restart`.