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

Describe random forests, Random forests : An ensemble of the classification...

Random forests : An ensemble of the classification or the regression trees (see the classification and regression tree methods) that have been fitted to the same n observations, bu

What is icmp, What is ICMP? ICMP is Internet Control Message Protocol. ...

What is ICMP? ICMP is Internet Control Message Protocol. It gives messaging and communication for protocols within the TCP/IP stacks. This is also the protocol that manages err

Work-sharing constructs in openmp, Work-Sharing Constructs A work-shari...

Work-Sharing Constructs A work-sharing construct distributes the implementation of the associated region between the members of the team that encounters it. A work-sharing cons

Explain the rad methodology with a suitable diagram, Question : (a) Exp...

Question : (a) Explain the ‘RAD' methodology with a suitable diagram. (b) One of the activities to be performed during Rapid Application Development is Rapid Business Analys

Data alignment in processor arrangements, Data Alignment Arrays are ali...

Data Alignment Arrays are aligned to templates by the ALIGN directive. The ALIGN directive is used to align elements of different arrays with each other, indicating that they s

Nics and network hardware, NICs AND NETWORK HARDWARE:  NIC is create f...

NICs AND NETWORK HARDWARE:  NIC is create for one kind of physical network. For example Ethernet interface may not be needed with token ring and similar ATM interface cannot b

Direct isp service through leased line, The most expensive method of access...

The most expensive method of accessing the Internet is to employ leased lines that directly connect to the ISP. This will enhance access rate to anywhere between 64 K and 1.5 Mbps,

Little spider, #question.what can we do with a spider when it red?.

#question.what can we do with a spider when it red?.

What are diagrams and trigrams, What are Diagrams and Trigrams? The mos...

What are Diagrams and Trigrams? The most ordinary two letter combinations are known as diagrams. e.g. th, in, er, re and an. The most common three letter combinations are known

Explain the OSI Model Facts, OSI Model Facts The OSI model classifies a...

OSI Model Facts The OSI model classifies and organizes the methods that hosts perform to maintain data for transport across the network. You should be familiar with the OSI m

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