The Domain Name System (DNS) Jason Hermance Nerces Kazandjian Long-Quan Nguyen

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "The Domain Name System (DNS) Jason Hermance Nerces Kazandjian Long-Quan Nguyen"

Transcription

1 The Domain Name System (DNS) Jason Hermance Nerces Kazandjian Long-Quan Nguyen

2 Introduction Machines find 32-bit IP addresses just peachy. Some Computer Science majors don t seem to mind either Normal people prefer names in general. easier to remember possibly more coherent So we need some sort of name-assigning scheme IP name geographical considerations

3 Names For Machines Early naming conventions assigned based on machines purpose accounting, talent, shipping, sales Low-level (IP) to High-level (name) A common concern in computer science. By 1986, 3100 officially registered, 6500 official aliases By today, hundreds of millions (of hundreds?)

4 Flat Namespace Just a sequence of characters Network Information Center (NIC) determined appropriate-ness of names (conflict, obscenity) Pros of a flat namespace names are short and convenient Cons of a flat namespace a single, predetermined (and thus finite) set of names a single site to handle all work and all traffic

5 Hierarchical Names & Delegation Of Authority What exactly are we aiming for? efficient name mapping autonomous name assignment Current system functions similar to a large corporation. split the responsibility autonomous operation Possible namespace partition pattern: local.site site- authorized by central authority local- authorized by the site ex. msn.com, laccd.edu

6 Subset Authority Keep subdividing to become manageable Let s try something like group.local.site site- authorized by central authority local- authorized by the site group- subdivision of local eg. moneycentral.msn.com, research.laccd.edu Not necessarily based on a physical mapping

7 Internet Domain Names The Domain Name System (DNS) we meet at last! Job 1: rules for syntax and authority Job 2: rules for implementing name-to-address mapping Syntax rules local label first, top domain last scope goes from small to big Let s take research.laccd.edu for example. research.laccd.edu is the lowest-level domain laccd.edu is the second-level domain edu is the top-level domain

8 Some common top-level domain names.com.edu.gov.net.org.us,.uk,.fr,.kz Commercial Organizations Educational Institutions US Government Major Network Support Centers Organizations Not Classified Country codes (geographic scheme) Have you been paying attention so far? If.us belongs to the USA, then it can delegate ca.us to California.

9 Top-Level Domains Two hierarchies: geographical and organizational countries are assigned a two-letter top-level domain organizations submit requests for registration So what went into getting python.ecs.csun.edu? CSUN: Hey, Internet. I want csun.edu. Internet: Okay, you got it. Hey CSUN, I want ecs.csun.edu. CSUN: Okay, you got it. Unnamed Python Admin: Hey, I want Yeah, yeah. You got it. Now go away.

10 Name Syntax And Type Houston, we have a problem. Multiple naming hierarchies leads to confusion. Confusion leads to anger. Anger leads to hate. Hate leads to suffering. mail.yahoo.com or nercesk.yahoo.com Let s introduce the idea of address type. The client specifies type in addition to the name to resolve. eg. machine, mailbox, user Can t determine type by syntax or number of labels alone. Hey, nercesk.yahoo.com could be a domain maybe.

11 Mapping Domain Names To Addresses Name server(s) program for name-to-address translation typically on a dedicated processor Name resolver: Client-side software for submitting requests Back to the corporation model and python.ecs.csun.edu root server sends request to top-level server (edu) top-level server sends request to level 2 (csun.edu) level 2 server sends request to level 3 (ecs.csun.edu) level 3 server sends request to level 4 (python.ecs.csun.edu) level 4 sends a response back up

12 Mapping Domain Names To Addresses Think of it as a tree structure. First level: root Second level: top-level domain Third level: local domain But this does not imply a direct physical connection. In actuality, not quite this involved root server knows enough to contact csun.edu directly

13 Domain Name Resolution Resolution query name to be resolved, class of the name, type of answer code for partial or complete translations Partial translation contact name servers one at a time Complete translation have name server system do the whole thing You gotta have at least one connection, pal.

14 Efficient Translation Do we have to go to root every single time? Think about dialing the area code each time, even for local calls. Going through the whole process is inefficient. Most name resolution is local. Root level would be overloaded. Higher-level failure need not be fatal. We can send the query locally first. If the current level can t resolve it, move to the parent.

15 Caching: The Key To Efficiency Why look the same thing up 100 times? Router : ARP Cache :: name server : DNS Cache DNS Cache entry domain name of server IP binding to that name But can t the IP binding change, you ask? Time To Live value given by authority depends on likelihood of change

16 Domain Name System Message Format More message format diagrams! 3-for-1 deal!

17 Compressed Name Format Domain names are stored as sequence of labels. Can be literal string or a pointer to a literal string. Literal string 1 st octet first 2 bits = 00, last 6 bits = length n next n octets label Rinse. Repeat. End with n = 0. Pointer to a literal string 1 st octet first 2 bits = 11, next 14 bits = integer pointer

18 Abbreviation Of Domain Names Outside domain name system introduced by client software List of possible suffixes to append to Possible uses include: convenient lookups restricted access

19 Inverse Mappings Working backwards like Jeopardy! Some problems with this Not every answer has a unique question. Even then, the server might not be able to provide one. We might have to search all the servers yuck. Implemented, but not really used

20 Pointer Queries One form of inverse mapping that s actually useful! Checks that the query is generated from an authorized domain. Mapping a client s IP to a domain name IP address aaa.bbb.ccc.ddd Pointer query ddd.ccc.bbb.aaa.in-addr.arpa But what if the local server is not in-addr.arpa or.arpa? Internet root domain servers are left in charge to make things efficient.

21 Some common object types A HINFO MINFO MX NS TXT 32-bit IP address CPU & OS information Mailbox/Mail List information Mail exchanger information Name of authoritative server for domain Uninterpreted string of ASCII text Let s try to be a little efficient for a moment. Servers will return any additionally known bindings in responses. Additional Information Section of responses

22 Obtaining Authority For A Subdomain In order to be granted authority for a second-level domain: agree to operate a domain name server that meets Internet standards know the addresses of subdomain servers and at least one root Servers can typically handle concurrent requests Processing older requests while accepting new ones Recursive requests, remember? There are more rules? Sheesh! All information must appear in at least two separate machines. Technically, the servers cannot have a single common point of failure.

23 Dynamic DNS Update And Notification Dynamic DNS update DHCP (Dynamic Host Configuration Protocol) assigns host obtains IP Sends update notice to DNS server NAT (Network Address Translation) sits before name server Coordinates translation with DNS server Multiple parties share administration Dynamic DNS notification DNS server propagates the update Sends notification to backup servers Backup servers request actual update

24 DNS Security Extensions (DNSSEC) Digital signature mechanism to protect DNS Check message authenticity Check data integrity Possible side effects include: No confidentiality from snooping (Deliberate-)Denial-Of-Service Public key encryption Server contains keys for authority zones further down Must manually configure keys for root servers.

A DNS Tutorial. Copyright

A DNS Tutorial.  Copyright http://ntrg.cs.tcd.ie/undergrad/4ba2/multicast/ Copyright Table of Contents What is a DNS?... 3 Why do we need a DNS?... 3 Why do computers prefer addresses based on numbers?... 3 What is a Domain Name,

More information

Chapter 23 The Domain Name System (DNS)

Chapter 23 The Domain Name System (DNS) CSC521 Communication Protocols 網 路 通 訊 協 定 Chapter 23 The Domain Name System (DNS) 吳 俊 興 國 立 高 雄 大 學 資 訊 工 程 學 系 Outline 1. Introduction 2. Names For Machines 3. Flat Namespace 4. Hierarchical Names 5.

More information

Motivation. Domain Name System (DNS) Flat Namespace. Hierarchical Namespace

Motivation. Domain Name System (DNS) Flat Namespace. Hierarchical Namespace Motivation Domain Name System (DNS) IP addresses hard to remember Meaningful names easier to use Assign names to IP addresses Name resolution map names to IP addresses when needed Namespace set of all

More information

ITEC310 Computer Networks II

ITEC310 Computer Networks II ITEC310 Computer Networks II Chapter 25 Domain Name System Department of Information Technology Eastern Mediterranean University Objectives 2/56 After completing this chapter you should be able to do the

More information

THE DOMAIN NAME SYSTEM DNS

THE DOMAIN NAME SYSTEM DNS Announcements THE DOMAIN NAME SYSTEM DNS Internet Protocols CSC / ECE 573 Fall, 2005 N. C. State University copyright 2005 Douglas S. Reeves 2 Today s Lecture I. Names vs. Addresses II. III. IV. The Namespace

More information

The Domain Name System (DNS)

The Domain Name System (DNS) The Domain Name System (DNS) Columbus, OH 43210 Jain@CIS.Ohio-State.Edu http://www.cis.ohio-state.edu/~jain/ 24-1 Overview Naming hierarchy hierarchy Name resolution Other information in name servers 24-2

More information

Understand Names Resolution

Understand Names Resolution Understand Names Resolution Lesson Overview In this lesson, you will learn about: Domain name resolution Name resolution process steps DNS WINS Anticipatory Set 1. List the host name of 4 of your favorite

More information

Introduction to Network Operating Systems

Introduction to Network Operating Systems As mentioned earlier, different layers of the protocol stack use different kinds of addresses. We can now see that the Transport Layer (TCP) uses port addresses to route data to the correct process, the

More information

Understanding DNS (the Domain Name System)

Understanding DNS (the Domain Name System) Understanding DNS (the Domain Name System) A white paper by Incognito Software January, 2007 2007 Incognito Software Inc. All rights reserved. Understanding DNS (the Domain Name System) Introduction...2

More information

DNS Protocol and Attacks

DNS Protocol and Attacks DNS Protocol and Attacks (1) DNS (Domain Name Service) 2004 presidential debate between vice president Dick Cheney and John Edward: Cheney: Well, the reason they keep mentioning Halliburton is because

More information

CS3250 Distributed Systems

CS3250 Distributed Systems CS3250 Distributed Systems Lecture 4 More on Network Addresses Domain Name System DNS Human beings (apart from network administrators and hackers) rarely use IP addresses even in their human-readable dotted

More information

Introduction to the Domain Name System

Introduction to the Domain Name System CHAPTER 14 The Domain Name System (DNS) handles the growing number of Internet users. DNS translates names, such as www.cisco.com, into IP addresses, such as 192.168.40.0 (or the more extended IPv6 addresses),

More information

19 Domain Name System (DNS)

19 Domain Name System (DNS) CHAPTER 9 Domain Name System (DNS) I n this chapter, we discuss the second application program, Domain Name System (DNS). DNS is a client/server application program used to help other application programs.

More information

Internetworking with TCP/IP Unit 10. Domain Name System

Internetworking with TCP/IP Unit 10. Domain Name System Unit 10 Domain Name System Structure 10.1 Introduction 10.2 Fully Qualified Domain Names (FQDNs) Generic Domains Country Domains 10.3 Mapping domain names to IP addresses 10.4 Mapping IP Addresses to Domain

More information

Networking Domain Name System

Networking Domain Name System System i Networking Domain Name System Version 5 Release 4 System i Networking Domain Name System Version 5 Release 4 Note Before using this information and the product it supports, read the information

More information

Distributed Name Services

Distributed Name Services Distributed Name Services A distinct service that is used by client processes to obtain attributes such as addresses of resources or objects when given their names Introducing Name Services Naming is fundamental

More information

Outline. Definition. Name spaces Name resolution Example: The Domain Name System Example: X.500, LDAP. Names, Identifiers and Addresses

Outline. Definition. Name spaces Name resolution Example: The Domain Name System Example: X.500, LDAP. Names, Identifiers and Addresses Outline Definition Names, Identifiers and Addresses Name spaces Name resolution Example: The Domain Name System Example: X.500, LDAP CS550: Advanced Operating Systems 2 A name in a distributed system is

More information

Lecture 2 CS 3311. An example of a middleware service: DNS Domain Name System

Lecture 2 CS 3311. An example of a middleware service: DNS Domain Name System Lecture 2 CS 3311 An example of a middleware service: DNS Domain Name System The problem Networked computers have names and IP addresses. Applications use names; IP uses for routing purposes IP addresses.

More information

Domain Name Service (DNS) Training Division, NIC New Delhi

Domain Name Service (DNS) Training Division, NIC New Delhi Domain Name Service (DNS) Training Division, NIC New Delhi Domain Name Service (DNS) I. History of DNS II. DNS structure and its components III. Functioning of DNS IV. Replicating DNS V. Dynamic update

More information

Names & Addresses. Names & Addresses. Names vs. Addresses. Identity. Names vs. Addresses. CS 194: Distributed Systems: Naming

Names & Addresses. Names & Addresses. Names vs. Addresses. Identity. Names vs. Addresses. CS 194: Distributed Systems: Naming Names & Addresses CS 9: Distributed Systems: Naming Computer Science Division Department of Electrical Engineering and Computer Sciences University of California, Berkeley Berkeley, CA 970-77 What is a?

More information

DNS Domain Name System

DNS Domain Name System Domain Name System DNS Domain Name System The domain name system is usually used to translate a host name into an IP address Domain names comprise a hierarchy so that names are unique, yet easy to remember.

More information

This time. Digging into. Networking. Protocols. Naming DNS & DHCP

This time. Digging into. Networking. Protocols. Naming DNS & DHCP This time Digging into Networking Protocols Naming DNS & DHCP Naming IP addresses allow global connectivity But they re pretty useless for humans! Can t be expected to pick their own IP address Can t be

More information

Domain Name System (DNS)

Domain Name System (DNS) Chapter 18 CSC465 Computer Networks Spring 2004 Dr. J. Harrison These slides are based on the text TCP/IP Protocol Suite (2 nd Edition) Domain Name System (DNS) CONTENTS NAME SPACE DOMAIN NAME SPACE DISTRIBUTION

More information

Part 5 DNS Security. SAST01 An Introduction to Information Security 2015-09-21. Martin Hell Department of Electrical and Information Technology

Part 5 DNS Security. SAST01 An Introduction to Information Security 2015-09-21. Martin Hell Department of Electrical and Information Technology SAST01 An Introduction to Information Security Part 5 DNS Security Martin Hell Department of Electrical and Information Technology How DNS works Amplification attacks Cache poisoning attacks DNSSEC 1 2

More information

DNS Basics. DNS Basics

DNS Basics. DNS Basics DNS Basics 1 A quick introduction to the Domain Name System (DNS). Shows the basic purpose of DNS, hierarchy of domain names, and an example of how the DNS protocol is used. There are many details of DNS

More information

DNS and BIND. David White

DNS and BIND. David White DNS and BIND David White DNS: Backbone of the Internet Translates Domains into unique IP Addresses i.e. developcents.com = 66.228.59.103 Distributed Database of Host Information Works seamlessly behind

More information

The Domain Name System (DNS)

The Domain Name System (DNS) The Domain Name System (DNS) Each Internet host is assigned a host name and an IP address Host names are structured character strings, e.g., www.cs.iastate.edu IP addresses are 32 bit integers, e.g., 129.186.3.6

More information

The Domain Name System

The Domain Name System DNS " This is the means by which we can convert names like news.bbc.co.uk into IP addresses like 212.59.226.30 " Purely for the benefit of human users: we can remember numbers (e.g., telephone numbers),

More information

Chapter 9: Name Services. 9.1 Introduction 9.2 Name services and the DNS 9.3 Directory services 9.6 Summary

Chapter 9: Name Services. 9.1 Introduction 9.2 Name services and the DNS 9.3 Directory services 9.6 Summary Chapter 9: Name Services 9.1 Introduction 9.2 Name services and the DNS 9.3 Directory services 9.6 Summary Learning objectives To understand the need for naming systems in distributed systems To be familiar

More information

Distributed Systems. 22. Naming. 2013 Paul Krzyzanowski. Rutgers University. Fall 2013

Distributed Systems. 22. Naming. 2013 Paul Krzyzanowski. Rutgers University. Fall 2013 Distributed Systems 22. Naming Paul Krzyzanowski Rutgers University Fall 2013 November 21, 2013 2013 Paul Krzyzanowski 1 My 15 MacBook Pro The rightmost computer on my desk Paul s aluminum laptop, but

More information

Domain Name System. 188lecture12.ppt. Pirkko Kuusela, Markus Peuhkuri, Jouni Karvo

Domain Name System. 188lecture12.ppt. Pirkko Kuusela, Markus Peuhkuri, Jouni Karvo Domain Name System 88lecture2.ppt Pirkko Kuusela, Markus Peuhkuri, Jouni Karvo S-38.88 - Computer Networks - Spring 2003 Outline What and why? Structure of DNS Management of Domain Names Name Service in

More information

- Domain Name System -

- Domain Name System - 1 Name Resolution - Domain Name System - Name resolution systems provide the translation between alphanumeric names and numerical addresses, alleviating the need for users and administrators to memorize

More information

Distributed Systems. 09. Naming. Paul Krzyzanowski. Rutgers University. Fall 2015

Distributed Systems. 09. Naming. Paul Krzyzanowski. Rutgers University. Fall 2015 Distributed Systems 09. Naming Paul Krzyzanowski Rutgers University Fall 2015 October 7, 2015 2014-2015 Paul Krzyzanowski 1 Naming things Naming: map names to objects Helps with using, sharing, and communicating

More information

Lesson 13: DNS Security. Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division

Lesson 13: DNS Security. Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division Lesson 13: DNS Security Javier Osuna josuna@gmv.com GMV Head of Security and Process Consulting Division Introduction to DNS The DNS enables people to use and surf the Internet, allowing the translation

More information

Domain Name System 2015-04-28 17:49:44 UTC. 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement

Domain Name System 2015-04-28 17:49:44 UTC. 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement Domain Name System 2015-04-28 17:49:44 UTC 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement Contents Domain Name System... 4 Domain Name System... 5 How DNS Works

More information

Chapter 24 The Domain Name System (DNS)

Chapter 24 The Domain Name System (DNS) Chapter 24 The Domain Name System (DNS) Columbus, OH 43210 Jain@CIS.Ohio-State.Edu http://www.cis.ohio-state.edu/~jain/ 24-1 Overview Naming hierarchy Server hierarchy Name resolution Other information

More information

Computer Networks: Domain Name System

Computer Networks: Domain Name System Computer Networks: Domain Name System Domain Name System The domain name system (DNS) is an application-layer protocol for mapping domain names to IP addresses DNS www.example.com 208.77.188.166 http://www.example.com

More information

Use Domain Name System and IP Version 6

Use Domain Name System and IP Version 6 Use Domain Name System and IP Version 6 What You Will Learn The introduction of IP Version 6 (IPv6) into an enterprise environment requires some changes both in the provisioned Domain Name System (DNS)

More information

Domain Name Server. Training Division National Informatics Centre New Delhi

Domain Name Server. Training Division National Informatics Centre New Delhi Domain Name Server Training Division National Informatics Centre New Delhi Domain Name Service (DNS) I. History of DNS II. DNS structure and its components III. Functioning of DNS IV. Possible Configurations

More information

DNS. The Root Name Servers. DNS Hierarchy. Computer System Security and Management SMD139. Root name server. .se name server. .

DNS. The Root Name Servers. DNS Hierarchy. Computer System Security and Management SMD139. Root name server. .se name server. . Computer System Security and Management SMD139 Lecture 5: Domain Name System Peter A. Jonsson DNS Translation of Hostnames to IP addresses Hierarchical distributed database DNS Hierarchy The Root Name

More information

Naming. Distributed Software Systems

Naming. Distributed Software Systems Naming Distributed Software Systems Naming Entities A name in a distributed system is a string of bits or characters that is used to refer to an entity Types of names Address: an access point of an entity

More information

Networking Domain Name System

Networking Domain Name System System i Networking Domain Name System Version 6 Release 1 System i Networking Domain Name System Version 6 Release 1 Note Before using this information and the product it supports, read the information

More information

To use DNS, you must have a DNS name server on your network.

To use DNS, you must have a DNS name server on your network. Configuring DNS Last Updated: December 14, 2012 The Domain Name System (DNS) is a distributed database in which you can map host names to IP addresses through the DNS protocol from a DNS server. Each unique

More information

Internet-Praktikum I Lab 3: DNS

Internet-Praktikum I Lab 3: DNS Kommunikationsnetze Internet-Praktikum I Lab 3: DNS Mark Schmidt, Andreas Stockmayer Sommersemester 2015 kn.inf.uni-tuebingen.de Motivation for the DNS Problem IP addresses hard to remember for humans

More information

Domain Name System. DNS is an example of a large scale client-server application. Copyright 2014 Jim Martin

Domain Name System. DNS is an example of a large scale client-server application. Copyright 2014 Jim Martin Domain Name System: DNS Objective: map names to IP addresses (i.e., high level names to low level names) Original namespace was flat, didn t scale.. Hierarchical naming permits decentralization by delegating

More information

Application Protocols in the TCP/IP Reference Model

Application Protocols in the TCP/IP Reference Model Application Protocols in the TCP/IP Reference Model File Transfer E-Mail Network Management WWW Virtual Terminal Name Service File Transfer HTTP FTP Telnet SMTP DNS SNMP TFTP Internet protocols TCP UDP

More information

Introduction to DNS CHAPTER 5. In This Chapter

Introduction to DNS CHAPTER 5. In This Chapter 297 CHAPTER 5 Introduction to DNS Domain Name System (DNS) enables you to use hierarchical, friendly names to easily locate computers and other resources on an IP network. The following sections describe

More information

1. Domain Name System

1. Domain Name System 1.1 Domain Name System (DNS) 1. Domain Name System To identify an entity, the Internet uses the IP address, which uniquely identifies the connection of a host to the Internet. However, people prefer to

More information

Application Protocols in the TCP/IP Reference Model. Application Protocols in the TCP/IP Reference Model. DNS - Concept. DNS - Domain Name System

Application Protocols in the TCP/IP Reference Model. Application Protocols in the TCP/IP Reference Model. DNS - Concept. DNS - Domain Name System Application Protocols in the TCP/IP Reference Model Application Protocols in the TCP/IP Reference Model File Transfer E-Mail Network Management Protocols of the application layer are common communication

More information

CSE 461 Naming and DNS. David Wetherall

CSE 461 Naming and DNS. David Wetherall CSE 461 Naming and DNS David Wetherall djw@cs.washington.edu Naming and DNS Focus: How do we resolve names to addresses Names and addresses Application DNS as a system design Transport Network Link Physical

More information

Teldat Router. DNS Client

Teldat Router. DNS Client Teldat Router DNS Client Doc. DM723-I Rev. 10.00 March, 2003 INDEX Chapter 1 Domain Name System...1 1. Introduction...2 2. Resolution of domains...3 2.1. Domain names resolver functionality...4 2.2. Functionality

More information

CS 640 Introduction to Computer Networks. Today s lecture. Lecture18. Domain Name System Overview

CS 640 Introduction to Computer Networks. Today s lecture. Lecture18. Domain Name System Overview Introduction to Computer Networks Lecture18 Today s lecture Domain Name System Overview The hierarchy of domain s DNS records The resolution process Domain Name System Overview What are s used for in general?

More information

Implementing Domain Name Service (DNS)

Implementing Domain Name Service (DNS) Implementing Domain Name Service (DNS) H C A 1 P T E R ITINERARY Objective 1.01 Objective 1.02 Objective 1.03 Install and Configure DNS for Active Directory Integrate Active Directory DNS Zones with Existing

More information

THE MASTER LIST OF DNS TERMINOLOGY. v 2.0

THE MASTER LIST OF DNS TERMINOLOGY. v 2.0 THE MASTER LIST OF DNS TERMINOLOGY v 2.0 DNS can be hard to understand and if you re unfamiliar with the terminology, learning more about DNS can seem as daunting as learning a new language. To help people

More information

Forouzan: Chapter 17. Domain Name System (DNS)

Forouzan: Chapter 17. Domain Name System (DNS) Forouzan: Chapter 17 Domain Name System (DNS) Domain Name System (DNS) Need System to map name to an IP address and vice versa We have used a host file in our Linux laboratory. Not feasible for the entire

More information

Naming. Today. l What s in a name l Flat naming l Structured naming l Attribute-based naming

Naming. Today. l What s in a name l Flat naming l Structured naming l Attribute-based naming Naming Today l What s in a name l Flat naming l Structured naming l Attribute-based naming Names, identifiers and addresses Names are used to denote entities in a system Hosts, printers, files, processes,

More information

DNS. Computer Networks. Seminar 12

DNS. Computer Networks. Seminar 12 DNS Computer Networks Seminar 12 DNS Introduction (Domain Name System) Naming system used in Internet Translate domain names to IP addresses and back Communication works on UDP (port 53), large requests/responses

More information

Chapter 25 Domain Name System. 25.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Chapter 25 Domain Name System. 25.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 25 Domain Name System 25.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 25.2 Figure 25.1 Example of using the DNS service 25-1 NAME SPACE To be unambiguous,

More information

Networking Domain Name System

Networking Domain Name System IBM i Networking Domain Name System Version 7.2 IBM i Networking Domain Name System Version 7.2 Note Before using this information and the product it supports, read the information in Notices on page

More information

Distributed Systems. 6. Name Services

Distributed Systems. 6. Name Services Distributed Systems 6. Name Services Werner Nutt 1 Naming Concepts Names = strings used to identify objects (files, computers, people, processes, objects) Textual names (human readable) used to identify

More information

Computer Networks Prof. S. Ghosh Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Lecture - 34 DNS & Directory

Computer Networks Prof. S. Ghosh Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Lecture - 34 DNS & Directory Computer Networks Prof. S. Ghosh Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Lecture - 34 DNS & Directory Good day. Today we will take up two topics, DNS and

More information

The Use of DNS Resource Records

The Use of DNS Resource Records International Journal of Advances in Electrical and Electronics Engineering 230 Available online at www.ijaeee.com & www.sestindia.org/volume-ijaeee/ ISSN: 2319-1112 Simar Preet Singh Systems Engineer,

More information

DNS/DNSSEC Tutorial. Rick Lamb & Champika Wijayatunga Kathmandu Nepal 27 January 2016 In conjunction with SANOG27

DNS/DNSSEC Tutorial. Rick Lamb & Champika Wijayatunga Kathmandu Nepal 27 January 2016 In conjunction with SANOG27 DNS/DNSSEC Tutorial Rick Lamb & Champika Wijayatunga Kathmandu Nepal 27 January 2016 In conjunction with SANOG27 2 Brief Overview of DNS The World s Network the Domain Name System + Internet Protocol numbers

More information

MCTS Guide to Configuring Microsoft Windows Server 2008 Active Directory. Chapter 9: Configuring DNS for Active Directory

MCTS Guide to Configuring Microsoft Windows Server 2008 Active Directory. Chapter 9: Configuring DNS for Active Directory MCTS Guide to Configuring Microsoft Windows Server 2008 Active Directory Chapter 9: Configuring DNS for Active Directory Objectives Describe the structure of Domain Name System Install and use the DNS

More information

Electronic Mail. The protocols used for Internet can be divided into three broad categories. transfer program. application.

Electronic Mail. The protocols used for Internet  can be divided into three broad categories. transfer program. application. Electronic Mail The protocols used for Internet email can be divided into three broad categories transfer program interface application interface application 33 The Simple Mail Transfer Protocol (SMTP)

More information

Domain Name System. CS 571 Fall 2006. 2006, Kenneth L. Calvert University of Kentucky, USA All rights reserved

Domain Name System. CS 571 Fall 2006. 2006, Kenneth L. Calvert University of Kentucky, USA All rights reserved Domain Name System CS 571 Fall 2006 2006, Kenneth L. Calvert University of Kentucky, USA All rights reserved DNS Specifications Domain Names Concepts and Facilities RFC 1034, November 1987 Introduction

More information

Domain Name System (or Service) (DNS) Computer Networks A15

Domain Name System (or Service) (DNS) Computer Networks A15 Domain Name System (or Service) (DNS) Computer Networks A15 DNS Outline Infrastructure Services DNS Hierarchical Structure Root Name Servers Top-Level Domain Servers Authoritative Name Servers Local Name

More information

Administrasi dan Manajemen Jaringan

Administrasi dan Manajemen Jaringan Administrasi dan Manajemen Jaringan 3. Domain Name System (DNS) M. Udin Harun Al Rasyid, Ph.D http://lecturer.eepis-its.edu/~udinharun udinharun@eepis-its.edu Lab Jaringan Komputer (C-307) Table of Contents

More information

Copyright International Business Machines Corporation 2001. All rights reserved. US Government Users Restricted Rights Use, duplication or disclosure

Copyright International Business Machines Corporation 2001. All rights reserved. US Government Users Restricted Rights Use, duplication or disclosure iseries DNS iseries DNS Copyright International Business Machines Corporation 2001. All rights reserved. US Government Users Restricted Rights Use, duplication or disclosure restricted by GSA ADP Schedule

More information

HTG XROADS NETWORKS. Network Appliance How To Guide: EdgeDNS. How To Guide

HTG XROADS NETWORKS. Network Appliance How To Guide: EdgeDNS. How To Guide HTG X XROADS NETWORKS Network Appliance How To Guide: EdgeDNS How To Guide V 3. 2 E D G E N E T W O R K A P P L I A N C E How To Guide EdgeDNS XRoads Networks 17165 Von Karman Suite 112 888-9-XROADS V

More information

THE DOMAIN NAME SYSTEM AT PURDUE UNIVERSITY-USE STANDARD

THE DOMAIN NAME SYSTEM AT PURDUE UNIVERSITY-USE STANDARD THE DOMAIN NAME SYSTEM AT PURDUE UNIVERSITY-USE STANDARD Issued January 14, 2011 from IT Networks and Security. Questions about this standard can be addressed to hostmaster@purdue.edu. I. Introduction:

More information

Fig 1A portion of the Internet domain name space.

Fig 1A portion of the Internet domain name space. 1 Asst. Lecturar ahmed S. Kareem DNS The Domain Name System Although programs theoretically could refer to hosts, mailboxes, and other resources by their network (e.g., IP) addresses, these addresses are

More information

An Introduction to the Domain Name System

An Introduction to the Domain Name System An Introduction to the Domain Name System Olaf Kolkman Olaf@nlnetlabs.nl October 28, 2005 Stichting NLnet Labs This Presentation An introduction to the DNS Laymen level For non-technologists About protocol

More information

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2 How DNS Works 210 out of 241 rated this helpful Updated: March 28, 2003 Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2 How DNS Works

More information

Names vs. Addresses. Flat vs. Hierarchical Space. Domain Name System (DNS) Computer Networks. Lecture 5: Domain Name System

Names vs. Addresses. Flat vs. Hierarchical Space. Domain Name System (DNS) Computer Networks. Lecture 5: Domain Name System Names vs. Addresses Computer Networks Lecture 5: Domain Name System Names are easier for human to remember www.umich.edu vs. 141.213.4.4 Addresses can be changed without changing names move www.umich.edu

More information

The Domain Name System

The Domain Name System The Domain Name System Antonio Carzaniga Faculty of Informatics University of Lugano October 9, 2012 2005 2007 Antonio Carzaniga 1 IP addresses and host names Outline DNS architecture DNS process DNS requests/replies

More information

Application Protocols in the TCP/IP Reference Model. Application Protocols in the TCP/IP Reference Model. DNS - Domain Name System

Application Protocols in the TCP/IP Reference Model. Application Protocols in the TCP/IP Reference Model. DNS - Domain Name System Application Protocols in the TCP/IP Reference Model Application Protocols in the TCP/IP Reference Model File Transfer E-Mail Network Management Protocols of the application layer are common communication

More information

CS3600 SYSTEMS AND NETWORKS

CS3600 SYSTEMS AND NETWORKS CS3600 SYSTEMS AND NETWORKS FALL 2011 Lecture 19: DNS Prof. Alan Mislove (amislove@ccs.neu.edu) Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang Human Involvement

More information

Domain Name Resolver (DNR) Configuration

Domain Name Resolver (DNR) Configuration CHAPTER 7 Domain Name Resolver (DNR) Configuration This chapter provides an overview of the information required to customize Cisco IOS for S/390. It includes these sections: Introducing the Domain Name

More information

How to Add Domains and DNS Records

How to Add Domains and DNS Records How to Add Domains and DNS Records Configure the Barracuda NextGen X-Series Firewall to be the authoritative DNS server for your domains or subdomains to take advantage of Split DNS or dead link detection.

More information

Applications and Services. DNS (Domain Name System)

Applications and Services. DNS (Domain Name System) Applications and Services DNS (Domain Name Service) File Transfer Protocol (FTP) Simple Mail Transfer Protocol (SMTP) Malathi Veeraraghavan Distributed database used to: DNS (Domain Name System) map between

More information

THE MASTER LIST OF DNS TERMINOLOGY. First Edition

THE MASTER LIST OF DNS TERMINOLOGY. First Edition THE MASTER LIST OF DNS TERMINOLOGY First Edition DNS can be hard to understand and if you re unfamiliar with the terminology, learning more about DNS can seem as daunting as learning a new language. To

More information

DNS. Computer networks - Administration 1DV202. fredag 30 mars 12

DNS. Computer networks - Administration 1DV202. fredag 30 mars 12 DNS Computer networks - Administration 1DV202 DNS History Who needs DNS? The DNS namespace How DNS works The DNS database The BIND software Server and client configuration The history of DNS RFC 882 and

More information

DNS Domain Name System

DNS Domain Name System DNS Domain Name System Domain names and IP addresses People prefer to use easy-to-remember names instead of IP addresses Domain names are alphanumeric names for IP addresses e.g., neon.cs.virginia.edu,

More information

ECE 4321 Computer Networks. Network Programming

ECE 4321 Computer Networks. Network Programming ECE 4321 Computer Networks Network Programming Name Space System.Net Domain Name System (DNS) To resolve computer naming Host database is split up and distributed among multiple systems on the Internet

More information

CS5008: Internet Computing

CS5008: Internet Computing CS5008: Internet Computing Lecture 12: Domains and DNS A. O Riordan, 2009, latest revision 2016 Some slides based on Fitzgerald and Dennis textbook Domains Purpose of Domains: Domains are administrative

More information

INTERNET DOMAIN NAME SYSTEM

INTERNET DOMAIN NAME SYSTEM INTERNET DOMAIN NAME SYSTEM http://www.tutorialspoint.com/internet_technologies/internet_domain_name_system.htm Copyright tutorialspoint.com Overview When DNS was not into existence, one had to download

More information

Domain Name System Richard T. B. Ma

Domain Name System Richard T. B. Ma Domain Name System Richard T. B. Ma School of Computing National University of Singapore CS 3103: Compute Networks and Protocols Names Vs. Addresses Names are easier for human to remember www.comp.nus.edu.sg

More information

L4 Domain Name System (DNS)

L4 Domain Name System (DNS) L4 Domain Name System (DNS) by T.S.R.K. Prasad EA C451 Internetworking Technologies 19/01/2013 References / Acknowledgements Sec 2.5: DNS, [Kurose] Sec 9.3.1: Name Service (DNS), [Peterson] Sec 12.3: DNS,

More information

Vorlesung Kommunikationsnetze Domain Name System

Vorlesung Kommunikationsnetze Domain Name System Picture 15 13 Vorlesung Kommunikationsnetze Domain Name System Prof. Dr. H. P. Großmann mit B. Wiegel sowie A. Schmeiser und M. Rabel Sommersemester 2009 Institut für Organisation und Management von Informationssystemen

More information

Chapter 2. Outline 9/9/14 DNS

Chapter 2. Outline 9/9/14 DNS Chapter 2 Outline DNS " Overview " Recursive and Iterative Queries " Resource record and DNS query " DNS Protocol " DNS Caching " DNS Services " Reverse DNS lookup 1 DNS (Domain Name System) Internet host

More information

How to Configure DNS Zones

How to Configure DNS Zones How to Configure DNS Zones The Barracuda NG Firewall DNS configuration object contains two predefined zones: _template and. To be able to edit and specify DNS zones within the Barracuda NG Firewall DNS

More information

The Application Layer. CS158a Chris Pollett May 9, 2007.

The Application Layer. CS158a Chris Pollett May 9, 2007. The Application Layer CS158a Chris Pollett May 9, 2007. Outline DNS E-mail More on HTTP The Domain Name System (DNS) To refer to a process on the internet we need to give an IP address and a port. These

More information

Domain Name System DNS

Domain Name System DNS CE443 Computer Networks Domain Name System DNS Behnam Momeni Computer Engineering Department Sharif University of Technology Acknowledgments: Lecture slides are from Computer networks course thought by

More information

Domain Name System. Proper use reduces intranet administration costs. Architecture DNS. Service. Flexible Scalable Extensible

Domain Name System. Proper use reduces intranet administration costs. Architecture DNS. Service. Flexible Scalable Extensible Domain Name System Proper use reduces intranet administration costs Architecture Flexible Scalable Extensible Service Standard Robust Efficient DNS Affordable Reliable Predictable The Internet continues

More information

Presented by Greg Lindsay Technical Writer Windows Server Information Experience. Presented at: Seattle Windows Networking User Group April 7, 2010

Presented by Greg Lindsay Technical Writer Windows Server Information Experience. Presented at: Seattle Windows Networking User Group April 7, 2010 Presented by Greg Lindsay Technical Writer Windows Server Information Experience Presented at: Seattle Windows Networking User Group April 7, 2010 Windows 7 DNS client DNS devolution Security-awareness:

More information

Networks 3. 2015 University of Stirling CSCU9B1 Essential Skills for the Information Age. Content

Networks 3. 2015 University of Stirling CSCU9B1 Essential Skills for the Information Age. Content Networks 3 Lecture Networks 3/Slide 1 Content What is a communications protocol? Network protocols TCP/IP High-level protocols Firewalls Network addresses Host name IP address Domain name system (DNS)

More information

DOMAIN NAME SYSTEM. Shipra Dey Computer Science & Engineering iamshipradey@gmail.com

DOMAIN NAME SYSTEM. Shipra Dey Computer Science & Engineering iamshipradey@gmail.com DOMAIN NAME SYSTEM Shipra Dey Computer Science & Engineering iamshipradey@gmail.com Siladtya Bhaumik Computer Science & Engineering siladtyabhaumik@gmail.com Abstract: This document briefly describes different

More information

ICS 351: Today's plan. DNS WiFi

ICS 351: Today's plan. DNS WiFi ICS 351: Today's plan DNS WiFi Domain Name System Hierarchical system of names top-level domain names include.edu,.org,.com,.net, and many country top-level domains root is just "." so the fully qualified

More information

Talk-101 User Guide. DNSGate

Talk-101 User Guide. DNSGate Talk-101 User Guide DNSGate What is DNSGate? DNSGate is a management interface to allow you to make DNS changes to your domain. The interface supports A, CNAME, MX and TXT records. What is DNS? DNS stands

More information