Data Networking/Spring 2015/GROUP4/DNS

DNS
DNS is application layer protocol which is used for domain naming for all the devices connected to the network.DNS translates our logical words into IP addresses and viceversa.The main function of it is to convert human form of understanding into machine suitable language.The DNS main function is to map the IP addresses to respective domains. DNS can be implemented in different levels of nae servers.

Behaviour of Protocol
DNS uses the services of UDP which is located at port number 53.The DNS request packet maps to hosts and fetches associate record and encapsulates it in the reply packet of UDP.

DNS Server
All the authoritative name servers uploads their important details like webservers,mailservers,canonical name servers into the DNS by registrars who are certified by icann.

Signaling
1.The client will generate dns query packet and send to local DNS.

2.Local DNS forwards this query to root name server ans a reply will be sent to local DNS which contains NS and A records of TLD servers.

3.Local DNS query the TLD nameserver and send reply to root name server.It also contain NS and A records.