1 Application Layer Mahalingam Mississippi State University, MS September 15, 2014
2 Outline 1 DNS Records DNS Components 2 Message Transfer Fetching s 3
3 Applications We will focus on 3 applications DNS
4 Domain Name Space DNS Records DNS Components Generic Countries int com edu gov mil org net jp us nl... sun yale acm ieee ac co oce vu eng cs eng jack jill keio nec cs ai linda cs csl flits fluit robot pc24
5 Domain Name Space DNS Records DNS Components DNS Root at the top of the inverted tree Top level domains generic (gtld) and country-code (cctld) New TLDs added rarely Names below TLDs can be purchased (if available) DNS is a distributed database of DNS records A database for every zone
6 Domain Name Service DNS Records DNS Components DNS (domain name service) provides domain-name to IP look-up Naming according to organizational boundaries - not physical IP addresses depend on physical location (issued by a ISP) DNS is an application uses UDP as the transport layer DNS servers queried by DNS clients.
7 DNS Zone DNS Records DNS Components name under the control of an entity msstate.edu is a zone Owner of zone msstate.edu authorized to create any name ending with msstate.edu. Can also delegate some names to other entities For example, cse.msstate.edu has been delegated A delegated name becomes a zone Root delegated gtld edu. gtld edu delegated msstate.edu. msstate.edu delegated cse.msstate.edu need not delegate all names (for example, eng.msstate.edu is not delegated, and so is still under the control of msstate.edu.
8 DNS Database DNS Records DNS Components Zone owner responsible for creating the zone database Zone database (or zone file, or, zone master file) is a list of DNS records Each record indicates name, type, and value There can be multiple records for the same name and type. DNS servers host the database typically every zone has one or more zone DNS servers
9 DNS Queries DNS Records DNS Components DNS servers can be queried by specifying a name and type For example, name disney.cse.msstate.edu, type A (A is for address) The response is a value corresponding to the name and type Possibly multiple values if multiple records exist for the same name and type. Query: name=cse.msstate.edu, type=a Response: name=cse.msstate.edu, type=a, value=
10 DNS Lookup DNS Records DNS Components Every zone provides it s parent information regarding how to reach the zone server. cse.msstate.edu provides information regarding name servers for cse.msstate.edu to parent zone msstate.edu Consequently root zone knows how to reach it s child edu edu knows how to reach it s child zone msstate.edu msstate.edu knows it s child zone cse.msstate.edu, etc.
11 Recursive and Iterative Queries DNS Records DNS Components Queries could be recursive or non-recursive Query by Q for name disney.cse.msstate.edu, type A Recursive: Q root edu msstate.edu cse.msstate.edu msstate.edu edu root Q Iterative: Q root ; Root Q response is direction to reach edu) Q edu direction to reach msstate.edu) Q msstate.edu direction to reach cse.msstate.edu Q cse.msstate.edu final (authoritative) answer to query Pros and Cons?
12 DNS Resource Record DNS Records DNS Components Each resource record is a five-tuple Domain Name TTL - how stable the record is Class - For Internet, it is IN Type - Many types (next slide) Value - Value corresponding to the type
13 Type Field in Resource Records DNS Records DNS Components SOA (start of authority) - details regarding primary source of info, contact addresses, serial number, flags and time-outs A (Address) - 32 bit IP address - there could be more that one A record (multiple IPs) MX (Mail Exchange) - Mail server for this domain NS (Name Server) CNAME - aliases (eg disney.cse.msstate.edu IN CNAME disney.cs.msstate.edu) PTR - allows for reverse-lookup HINFO - additional info about the machine TXT - Whatever else you want to add!
14 Sample DNS Database Entry DNS Records DNS Components
15 DNS Components DNS Records DNS Components Domain Registrars: sell domain names Zone authority/owner: Creates DNS records pertaining to a zone all records entered in a zone master file Authoritative DNS servers (zone servers): Servers run by the authority. Serves DNS records from the zone master file(s) Root name servers are authoritative for root domain. A gtld name server is authoritative for the gtld. Local DNS servers: typically operated by ISPs (performs iterative queries, caches responses) Stub resolvers: in every host (queries the local DNS server) dig (DNS query tool. Download, install and play with it).
16 Authoritative Name Servers DNS Records DNS Components root servers: A.ROOT-SERVERS.NET, B.ROOT-SERVERS.NET, M.ROOT-SERVERS.NET edu name servers: a.gtld-servers.net., c.gtld-servers.net,... msstate.edu: ns1.msstate.edu, trantor.umd.edu, ns2.msstate.edu. cnn.com: twdns-01.ns.aol.com, twdns-02.ns.aol.com,...
17 DNS Query and Response DNS Records DNS Components Application (for example, browser) requires IP address of groklaw.net Application makes a call to a stub resolver: gethostbyname(groklaw.net) Stub resolver checks in its cache. If A-type record for groklaw.net is found, gethostbyname() returns with the record Else sends query to a local DNS server (LDNS) If LDNS has the answer in it s cache it responds to stub resolver s query.
18 DNS Query and Response DNS Records DNS Components If not found in cache, LDNS maskes iterative queries LDNS sends a query groklaw.net A to a root server Root server sends a response with info regarding ANSs for net LDNS sends the query groklaw.net A to a net name server, and receives info regarding ANSs for groklaw.net LDNS sends a query groklaw.net A to the ANS and receives the desired response. LDNS (caches answer and) sends the response to the stub resolver, gethostbyname(groklaw.net) returns (recall hostent structure returned by gethostbyname())
19 DNS Query/Response Format DNS Records DNS Components Both query and response have the same format Five sections: HEADER QUESTION ANSWER AUTHORITY ADDITION
20 dig DNS Records DNS Components Windows: dig NS (query for root name servers) dig edu NS dig msstate.edu A dig msstate.edu NS
21 dig groklaw.net DNS Records DNS Components QUESTION SECTION: groklaw.net IN A ANSWER SECTION: groklaw.net IN A AUTHORITY: groklaw.net IN NS ns.unc.edu. groklaw.net IN NS ns2.unc.edu. ADDITION: ns.unc.edu IN A ns2.unc.edu IN A
22 Message Transfer Fetching s
23 Basic Components Message Transfer Fetching s Mail clients and servers Two types of clients and servers (sending and receiving) SMTP (simple mail transfer protocol) servers for sending mail IMAP/POP3 servers for making received mails accessible to clients SMTP servers accept s from sending clients Receiving clients fetch from IMAP/POP3 servers Web based services are also popular. RFC 822 specifies formats (for sending to SMTP servers)
24 RFC 822 Header Message Transfer Fetching s
25 RFC 822 Header - Other Fields Message Transfer Fetching s
26 MIME Extensions Message Transfer Fetching s Only printable characters are permitted in RFC 822 format. MIME - for Content description and encoding Content transfer encoding usually base-64 encoding.
27 Message Transfer Fetching s RFC 822 Header MIME Extensions
28 MIME Types Message Transfer Fetching s
29 Message Transfer Fetching s SMTP - Simple Message Transfer Protocol TCP, port 25 Supported commands HELP HELO MAIL FROM RCPT TO DATA
30 SMTP Restrictions Message Transfer Fetching s Max Message length - 64 KB Recursive mailing lists ESMTP (Extended SMTP) New command EHLO - if not accepted, defaults to SMTP.
31 Sending an Message Transfer Fetching s To send an to What is the mail server for somewhere.com? Make a DNS query for (somewhere.com, MX ) e.g., somewhere.com, 82345, IN, MX, mail.something.net Make DNS query for (mail.something.net, A) to determine IP address of mail server e.g. response, mail.something.net,3245, IN, A, Connect to SMTP server (port 25) at IP address use RCPT TO: xyz to check if xyz is a valid address in the domain somewhere.com send in RFC 822 format.
32 Fetching s Message Transfer Fetching s POP3 IMAP Webmail
33 Mail Transfer Modes Message Transfer Fetching s SMTP Internet Message transfer agent User agent (a) Sending host Permanent connection Mailbox Receiving host SMTP Internet Message transfer agent POP3 server POP3 User agent (b) Sending host Mailbox ISP's machine Dial-up connection User's PC
34 POP3 / IMAP Message Transfer Fetching s POP - Post Office Protocol - RFC 1939 POP3 commands - USER, PASS, LIST, RETR, DELE, QUIT IMAP - Internet Message Access Protocol - RFC 2060 Complex, partial message downloads MS Exchange server, GroupWise, Simbra
36 A Good Tutorial HTTP Made Really Easy
37 GET To fetch a page from cse.msstate.edu perform DNS query to determine IP address. Connect to port 80 and send a HTTP query. GET / HTTP/1.1\r\n Host: cse.msstate.edu\r\n User-Agent: Mozilla/5.0 Accept: Accept-Language: Accept-Charset: Keep-Alive: 300\r\n Connection: keep-alive\r\n \r\n First two lines are mandatory in every request. Why is second line (Host:) mandatory? Multiple websites may be hosted in a single machine (same IP and port).
38 Header in HTTP Response HTTP/ OK Date: Server:Apache X-Powered-By:PHP / OpenSSL Keep-Alive:timeout=15 Connection: Keep-Alive Transfer-Encoding: Content-Type: \r\n
39 HTTP Status codes
40 HTTP Request Methods
41 HTTP Headers
42 URLs - Uniform Resource Locators
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
Computer Networks 1 (Mạng Máy Tính 1) Lectured by: Dr. Phạm Trần Vũ MEng. Nguyễn CaoĐạt 1 Lecture 10: Application Layer 2 Application Layer Where our applications are running Using services provided by
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
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
Overview Domain Name System We look first at how the Domain Name System (DNS) is implemented and the role it plays in the Internet We examine some potential DNS vulnerabilities and in particular we consider
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.
1 Introduction: Network Applications Some Network Apps E-mail Web Instant messaging Remote login P2P file sharing Multi-user network games Streaming stored video clips Internet telephone Real-time video
Recap SMTP and email The Application Layer: DNS Smith College, CSC 9 Sept 9, 0 q SMTP process (with handshaking) and message format q Role of user agent access protocols q Port Numbers (can google this)
Application Layer Domain Name System Domain Name System (DNS) Problem Want to go to www.google.com, but don t know the IP address Solution DNS queries Name Servers to get correct IP address Essentially
Domain Name System (DNS) Instructor: Anirban Mahanti Office: ICT 745 Email: firstname.lastname@example.org Class Location: ICT 121 Lectures: MWF 12:00 12:50 Notes derived from Computer Networking: A Top Down
DATA COMMUNICATOIN NETWORKING Instructor: Ouldooz Baghban Karimi Course Book: Computer Networking, A Top-Down Approach By: Kurose, Ross Introduction Course Overview Basics of Computer Networks Internet
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
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
Hostnames CSCE 515: Computer Network Programming ------ Address Conversion Function and DNS RFC 1034, RFC 1035 Wenyuan Xu http://www.cse..edu/~wyxu/ce515f07.html Department of Computer Science and Engineering
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)
1/30 DNS : Domain Name System Surasak Sanguanpong nguan@.ac.th http://www...ac.th/~nguan Last updated: May 24, 1999 Outline 2/30 DNS basic name space name resolution process protocol configurations Why
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.
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
DNS and E-mail Interface User Guide Document Revision 04 // 2012 www.twcbc.com back back to TOC to TOC Header Text and Info Table of Contents 1. Introduction 3 2. Accessing the Application 4 3. Working
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,
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
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
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
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
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
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
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
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
CPSC 360 Network Programming Applications & Application-Layer Protocols: The Domain Name System and Peerto-Peer Systems Michele Weigle Department of Computer Science Clemson University email@example.com
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,
DNS " This is the means by which we can convert names like news.bbc.co.uk into IP addresses like 184.108.40.206 " Purely for the benefit of human users: we can remember numbers (e.g., telephone numbers),
Domain Name System (DNS) Reading: Section in Chapter 9 RFC 1034, STD 13 Name Syntax and rules for delegating authority over names Specify implementation of a distributed system that maps names to addresses
Domain Name System (DNS) Fundamentals Mike Jager Network Startup Resource Center firstname.lastname@example.org These materials are licensed under the Creative Commons Attribution-NonCommercial 4.0 International
Computer Networks Instructor: Niklas Carlsson Email: email@example.com Notes derived from Computer Networking: A Top Down Approach, by Jim Kurose and Keith Ross, Addison-Wesley. The slides are adapted
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
Basic DNS Course Module 1 Ron Aitchison ZYTRAX, Inc. Page 1 of 24 The following are the slides used in this Module of the course. Some but not all slides have additional notes that you may find useful.
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
Institute of Telecommunications Warsaw University of Technology 2015 internet technologies and standards Piotr Gajowniczek Andrzej Bąk Michał Jarociński Internet application layer the email service The
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
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
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.
DNS Resolving using nslookup Oliver Hohlfeld & Andre Schröder January 8, 2007 Abstract This report belongs to a talk given at the networking course (Institue Eurecom, France) in January 2007. It is based
QAFQAZ UNIVERSITY Computer Engineering Department Internet Technologies Internet Protocols and Services Dr. Abzetdin ADAMOV Chair of Computer Engineering Department firstname.lastname@example.org http://ce.qu.edu.az/~aadamov
Domain Name System (DNS) Session-1: Fundamentals Ayitey Bulley email@example.com Computers use IP addresses. Why do we need names? Names are easier for people to remember Computers may be moved between
CS43: Computer Networks Email Kevin Webb Swarthmore College September 24, 2015 Three major components: mail (MUA) mail transfer (MTA) simple mail transfer protocol: SMTP User Agent a.k.a. mail reader composing,
Mail agents Introduction to Internet Mail Philip Hazel University of Cambridge MUA = Mail User Agent Interacts directly with the end user Pine, MH, Elm, mutt, mail, Eudora, Marcel, Mailstrom, Mulberry,
File Transfer: FTP FTP: the file transfer protocol at host FTP interface FTP client local file system file transfer FTP remote file system transfer file to/from remote host client/ model client: side that
3. The Domain Name Service n Overview and high level design n Typical operation and the role of caching n Contents of DNS Resource Records n Basic message formats n Configuring/updating Resource Records
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,
Domain Name System Security Guevara Noubir Network Security Northeastern University 1 Domain Name System DNS is a fundamental applica=on layer protocol Not visible but invoked every =me a remote site is
Domain Name System (or Service) (DNS) Computer Networks Term B10 DNS Outline DNS Hierarchial Structure Root Name Servers Top-Level Domain Servers Authoritative Name Servers Local Name Server Caching and
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
Networking Primer* *caveat: this is just a brief and incomplete introduction to networking to help students without a networking background learn Network Security. How do I get to www.randomsite.com? Local
Application Layer: DNS Prof. Andrzej Duda firstname.lastname@example.org http://duda.imag.fr 1 Overview Learn about protocols by examining popular application-level protocols DNS - name service 2 Applications and application-layer
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
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
Names vs. Addresses Computer Networks Lecture 5: Domain Name System Names are easier for human to remember www.umich.edu vs. 220.127.116.11 Addresses can be changed without changing names move www.umich.edu
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., 18.104.22.168
How to set up the Integrated DNS Server for Introduction Getting Started Peplink Balance has a built-in DNS server for inbound link load balancing. You can delegate a domain s NS/SOA records, e.g. www.mycompany.com,
Internet Security  VU 184.216 Engin Kirda email@example.com Christopher Kruegel firstname.lastname@example.org Administration Challenge 2 deadline is tomorrow 177 correct solutions Challenge 4 will
Information Network I Application layer Web 2.0 Youki Kadobayashi NAIST They re revolving around the web, after all Name any Internet-related buzz: Cloud computing Smartphone Social media... You ll end
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
CS326e Quiz 5 The first correct 10 answers will be worth 1 point each. Each subsequent correct answer will be worth 0.2 points. Circle the correct answer. UTEID The transfer of an html file from one host
Evolution of the WWW Communication in the WWW World Wide Web (WWW) Access to linked documents, which are distributed over several computers in the History of the WWW Origin 1989 in the nuclear research
CS3600 SYSTEMS AND NETWORKS FALL 2011 Lecture 19: DNS Prof. Alan Mislove (email@example.com) Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang Human Involvement
Application layer Goals: Conceptual aspects of network application protocols Client server paradigm Service models Learn about protocols by examining popular application-level protocols HTTP DNS Application-layer
DNS: Domain Name System People: many identifiers: SSN, name, passport # Internet hosts, routers: IP address (32 bit) - used for addressing datagrams name, e.g., ww.yahoo.com - used by humans Q: map between
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
Cours du 22 novembre Couche application DNS Application Layer 2-2 DNS: domain name system people: many identifiers: SSN, name, passport # Internet hosts, routers: IP address (32 bit) - used for addressing
CS 348: Computer Networks - DNS; 22 nd Oct 2012 Instructor: Sridhar Iyer IIT Bombay Domain Name System Map between host names and IP addresses People: many identifiers: name, Passport #, Internet hosts:
1 Homework 2 assignment for ECE374 Posted: 02/20/15 Due: 02/27/15 ote: In all written assignments, please show as much of your work as you can. Even if you get a wrong answer, you can get partial credit
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
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
Application layer Protocols application transport data link physical Network Applications and Application Layer Protocols Network applications: running in end systems (hosts) distributed, communicating
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
Security Analysis of DNS & Applications/Email EE 122: Intro to Communication Networks Fall 2007 (WF 4-5:30 in Cory 277) Vern Paxson TAs: Lisa Fowler, Daniel Killebrew & Jorge Ortiz http://inst.eecs.berkeley.edu/~ee122/
Service Processes and Threads: execution of applications or services Communication: information exchange for coordination of processes But: how can client processes (or human users) find the right server
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
Naming and the DNS Focus How do we name hosts etc.? Application Presentation Topics Session Domain Name System (DNS) Email/URLs Transport Network Data Link Physical Ldns.1 Names and Addresses 43 name address
CSE 265: System & Network Administration DNS The Domain Name System History of DNS What does DNS do? The DNS namespace BIND software How DNS works DNS database Testing and debugging (tools) DNS History
Motivation 2 cs.princeton.edu User 1 user @ cs.princeton.edu Name server Mail program 22.214.171.124 3 TCP 126.96.36.199 4 188.8.131.52 5 IP Users can t remember IP addresses - Need to map symbolic names (www.stanford.edu)
Training Installing and Setting up Microsoft DNS Server Introduction Versions Used Windows Server 2003 Setup Used i. Server Name = martini ii. Credentials: User = Administrator, Password = password iii.
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?
Computer Networks: Domain Name Service (DNS) CS 3516 D- term 2013 Instructor: Krishna Venkatasubramanian Quiz 2 DNS: domain name system people: many identifiers: SSN, name, passport # Internet hosts, routers:
Domain Name System Heng Sovannarith firstname.lastname@example.org Introduc:on to DNS Domain Name System is a distributed database system that can be serve as the founda:on for name resolu:on in a TCP/IP Network.