Dns records and messages - application layer, Computer Networking

Assignment Help:

DNS Records  and Messages

Two types  of records  are used DNS. The  question records  are used in the question  section of the query and response  messages. The resource  records  are used in the  answer  authoritative  and additional  information sections of the  response  message.

Question Record: A questions records in used by the client  to get  information  from a server. This contains the domain  name.

Resource Record: Each domain  name is  associated  with a  record  called  the resource  record. The server database  consists  or resource  returned by the server to the client.

A resource  records is a quadruple that contains the  following  fields.

Name , Value , Type , TTL

TTL  is the time  to live of  the resource records. It determines  when a resource  should be  removed  from a cache form a  cache. In the example  records given below  we ignore the TTL  field.

The  meaning of  name  and value  depend on  type:

If a DNS  server is authoritative for a  particular host name  then the DNS  server will  contain  a type a record for the  hostname. If a server is not authoritative  for a hostname  then the  server will contain a type NS record for the  domain  that includes the hostname. It  will also  contain  a Type  a record that provides the IP address of the DNS  server in the value field of the NS  records. As an example suppose an edu TLD server is not  authoritative for the host gain cs un mass edu. Then this server will contains  a record for a  domain that includes the host cs mass. Edu. For example  ( umass edu dns unmass. Edu  NS) the du TLD server would  also contain a Type a record which maps the DNS. Server dns  umass.edu to an IP address for example  ( dns umass edu 128.119.111A)


Related Discussions:- Dns records and messages - application layer

Define transport layer of osi model, Q. Define transport layer of osi model...

Q. Define transport layer of osi model? - The transport layer regulates information flow to makes sure end-to-end connectivity between host applications reliably and accurately

Define the terms unicasting and multiccasting, Define the terms Unicasting,...

Define the terms Unicasting, Multiccasting and Broadcasting? If the message is sent from a source to a one destination node, it is called Unicasting. If the message is sent

Write a long note on internet and privacy, Question 1 Write a long note on...

Question 1 Write a long note on computers in television development Question 2 Write a long note on the ‘Steadicam' Question 3 Write a long note on Internet and pr

Fat tree, Fat tree It is a modified version of the tree network. In thi...

Fat tree It is a modified version of the tree network. In this group the bandwidth of edge (or the connecting wire among nodes) increases towards the root. It is a more practic

What are the basic key functions of data link layer, Q. What are the basic ...

Q. What are the basic key functions of data link layer? Ans: Data link layer transfers data in a structured and reliable manner so that the service given by the physical layer

Transport protocols - udp and tcp, Most real-life applications are built on...

Most real-life applications are built on top of the UDP and TCP transport protocols. UDP, which stands for User Datagram Protocol, provides the capability of delivering individual

Hierarchy of dns servers application layer , Hierarchy of DNS Servers ...

Hierarchy of DNS Servers DNS uses a large number of server organized in hierarchical  fashion  and distribution  around the world. No single DNS server has all  of the  mappin

Hypercube network and properties, Hypercube Network The hypercube archi...

Hypercube Network The hypercube architecture has played a vital role in the development of parallel processing and is still not much popular and influential. The highly symmetr

Determine the term - experimental neuropsychology, Determine the term - Exp...

Determine the term - Experimental neuropsychology This is an approach which uses methods from experimental psychology to uncover the relationship among the nervous system and c

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd