Thursday, 5 December 2013

DNS LOOKUP AND REVERSE DNS LOOKUP

                                             DNS lookup
It stands for domain name server. It is basically a resource for converting friendly hostnames (like google.com) which humans can easily understand  into IP addresses that machine needs to communicate to the host. When you type www.google.com in the location bar of browser, the browser performs a DNS lookup or search to find the machine-readable IP address so that it can communicate with the host. This means the browser cannot communicate with a host without the IP address. Hence in order to perform the DNS lookup, the browser contact the DNS server through your IPS and looks for the IP conversion of the hostname it wants to contact.
          The server on which the browser first looks for a hostname to IP translation is the primary server DNS server. If this doesn’t show match, then it contact to secondary DNS server. If a match is found in secondary DNS server, then the primary server updates its database. So that it doesn’t have to contact the secondary server again for the same match.
         DNS lookup is simply the process of converting the human-understandable hostnames into the machine-understandable .Thus you can say that a DNS look up convert a hostname into an IP addresses.
                        REVERSE DNS LOOKUP  
        It is a simply convert machine-understandable IP address into its human-understandable hostname.      

No comments:

Post a Comment