Firefox uses DNS process to translate the domain name into IP address. For example, if you type www.anakblog.com into your firefox address bar, the DNS process will perform a lookup to fine the IP address in which the data for www.anakblog.com website is stored. Everytime you tipe a new address or click a link to a new website, Firefox's DNS will find the IP address of the website.
Now if you want to configure DNS cache for your Mozilla Firefox Browser, all you need to know is the config parameters for its DNS cache:
- Network.dnsCacheExpiration - defines the duration of the DNS entry will be kept in the DNS cache
- network.dnsCacheEntries - defines the number of entries in the DNS cache table
And to change above parameters, just read following steps:
- Type "about:config" in the address bar and press "Enter". A preference table should appear in the window.
- Right Click on the Preferences Table. Select: New >> Integer It shoud ask for the preference name
- Type "Network.dnsCacheExpiration" without the quotes into the preference name. It should ask for the integer value.
- Type 1800 into as Integer value to increase the cache expiration to 30 minutes (1800 seconds). You can configure it to 3600 to increase it to one hour.
- Repeat steps 2 to 4 for preference name: network.dnsCacheEntries and set the integer value to 1000 This will allow up to 1000 DNS entries will be stored in DNS cache.
- Close the window to restart your browser.
More about DNS:
The Domain Name System (DNS) is a hierarchical naming system for computers, services, or any resource participating in the Internet. It associates various information with domain names assigned to such participants. Most importantly, it translates domain names meaningful to humans into the numerical (binary) identifiers associated with networking equipment for the purpose of locating and addressing these devices world-wide. An often used analogy to explain the Domain Name System is that it serves as the "phone book" for the Internet by translating human-friendly computer hostnames into IP addresses. For example, www.example.com translates to 126.96.36.199. 
 Domain Name System. (2009, April 25). In Wikipedia, The Free Encyclopedia. Retrieved 08:14, April 27, 2009, from http://en.wikipedia.org/w/index.php?title=Domain_Name_System&oldid=286061228