DNS (Domain Name System), is the service which translates between Internet names and Internet addresses.

The Domain Name System is one of the foundations of the internet. It is the system that allows the translation of human-readable domain names into machines-readable IP addresses and the reverse translation of IP addresses into domain names.

When you surf on net the dns records will be cache inside your pc. This methods will make your browsing much faster because you wont need to resolve the dns each time you surf a site or network. But sometimes caching can be an issue when certain network change their ip address. You can resolve this by clearing or flushing the dns. Here a few simple command on how to flush your dns cache in PC, Mac & *nix operating systems.

Windows PC

Start > Run > ipconfig /flushdns

Mac

Open Console lookupd -flushcache

Linux

restart nscd daemon.
Open Console /etc/rc.d/init.d/nscd restart

Stop dnscache via Windows services

For windows, If you are having frequent issue with dns caching you can disabled the dns-client caching services with

• Start > Run net stop dnscache
• or manually stopping the services via services.msc (microsoft services console).
  sc servername stop dnscache