the university of akron summit college business technology dept
Download
Skip this Video
Download Presentation
The University of Akron Summit College Business Technology Dept.

Loading in 2 Seconds...

play fullscreen
1 / 27

ame system/service - PowerPoint PPT Presentation


  • 283 Views
  • Uploaded on

The University of Akron Summit College Business Technology Dept. 2440: 141 Web Site Administration Domain Name System Instructor: Enoch E. Damson. Domain Name System/Service. The Domain Name System (DNS) is used to translate host names to IP addresses on the Internet

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'ame system/service' - RexAlvis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
the university of akron summit college business technology dept

The University of AkronSummit CollegeBusiness Technology Dept.

2440: 141Web Site Administration

Domain Name System

Instructor: Enoch E. Damson

Domain Name System

domain name system service
Domain Name System/Service
  • The Domain Name System (DNS) is used to translate host names to IP addresses on the Internet
    • Also called name resolution or address resolution
    • Created in the early 1980s
    • The first UNIX implementation (Berkeley Internet Name Domain-BIND- server) was created in 1984
    • Whenever a host is added, a configuration file has to be manually changed
    • A host represents a service on a server such as FTP or a Web server
    • There can be many hosts on a single computer
  • Windows networks use DNS to resolve computer names on a LAN
    • DNS in Windows is designed to be dynamic – as computers are added to the network, DNS automatically changes

Domain Name System

clients
Clients
  • On your PC, the TCP/IP configuration contains the address(es) of your DNS server(s)
  • Whenever you use a URL, whether in a browser, or a utility such as ping, DNS servers are used

Domain Name System

structure of the internet domains
Structure of the Internet Domains
  • DNS is organized into a hierarchical structure that defines domains
  • DNS arranges host names in a hierarchy to make them easier to manage and find
  • The DNS hierarchical naming system consists of three levels:
    • Root level
    • Top-level domain (TLD)
    • Second-level domain (SLD)

Domain Name System

domain namespaces
Domain Namespaces
  • The root level domain is "."
    • Significant in creating DNS files
  • Top-level domains identifies the most general part of the domain name
    • It identifies the category of the domain name
    • The first few original domains were: com, org, edu, gov, mil, and net
  • Second-level domains are used to identify the individual or company with the domain name
    • E.g. microsoft.com, uakron.edu
    • A subdomain is a further division of a second-level domain
      • E.g. gozips.uakron.edu

Domain Name System

domain namespaces6
Domain Namespaces…
  • Second-level domains, such as uakron.edu have control over naming within their domain
  • Create hosts such as www, ftp
  • A name such as www.uakron.edu is a fully qualified domain name (FQDN)
  • We could create subdomains such as www3
    • E.g. www3.uakron.edu

Domain Name System

top level domains
Top-Level Domains
  • A Web server is commonly named www
  • The original top-level domain (TLD) categories that were available on the Internet included:
    • com – commercial domains
    • org – mostly nonprofit organizations
    • net – usually ISPs and other network-supported companies
    • edu – educational institutions
    • gov – U.S. federal government organizations
    • mil – U.S. military organizations
    • in-addr.arpa – for reverse lookups
  • http://www.iana.org/domains/root/db

Domain Name System

top level domains8
Top-Level Domains…
  • The Internet Corporation for Assigned Names and Numbers (ICANN) later approved other TLDs below:
    • biz – businesses
    • info – open to anyone
    • name – personal registrations
    • pro – Licensed professionals, such as doctors, lawyers, etc
    • aero – anything related to air transport
    • museum – Museums
    • coop – cooperative businesses such as credit unions

Domain Name System

top level domains9
Top-Level Domains…
  • There are over 200 country-specific domains
  • Some standard country-specific TLDs include:
    • .au – Australia
    • .ca – Canada
    • .jp – Japan
    • .sw – Sweden
    • .uk – United Kingdom
    • .us – United States (mainly by local and state government agencies and k-12 schools)

Domain Name System

domain name registration
Domain Name Registration
  • ICANN (Internet Corporation for Assigned Names and Numbers) is a non-profit organization that coordinates Internet unique identifiers
  • ICANNis funded primarily through fees paid to ICANN by registrars and registry operators
    • Registrars are companies (e.g., GoDaddy, Google, Network Solutions) with which consumers register domain names
    • Registry operators are companies and organizations who operate and administer the master database of all domain names registered in each top level domain (for example VeriSign, Inc. operates .com and .net, Public Interest Registry operates .org, and Neustar, Inc. operates .biz)
  • http://www.icann.org/en/registrars/accredited-list.html (ICANN accredited Registrars)

Domain Name System

domain name registration11
Domain Name Registration…
  • Domain names are available on a first-come, first-served basis
  • The Internet Assigned Numbers Authority (IANA) is responsible for the global coordination of the DNS Root, IP addressing, and other Internet protocol resources
  • Some of the things needed include:
    • A non-registered domain name
    • A valid email address
    • Names and addresses of the primary and secondary DNS servers
    • A credit card (to pay online)

Domain Name System

host names
Host Names
  • The first portion of a URL is typically a host name
  • Typically different from the name of the computer
  • Many hosts can be associated with the same Web server

Domain Name System

dns components
DNS Components
  • Name server – also known as DNS server
    • supports name-to-address and address-to-name resolution
  • Name resolver – also called DNS client
    • Can contact DNS server to lookup name
    • Used by browsers, e-mail clients, and client utilities such as ping and tracert

Domain Name System

dns servers that define the internet
DNS Servers that Define the Internet
  • The two main DNS servers that define the Internet are:
    • Primary servers
    • Secondary servers
      • Primary and secondary servers store the host names used on the Internet
  • The two main DNS servers that resolve domain names are:
    • Caching servers
    • Forwarding servers
      • Caching and forwarding servers search the Internet for host names

Domain Name System

primary and secondary servers
Primary and Secondary Servers
  • Primary Server
    • Defines the hosts for the domain
      • Maintains the database for the domain
    • It has authority for the domain
  • Secondary Server
    • Gets data from primary server
    • Provides fault tolerance and load distribution
    • Required for Internet domains

Domain Name System

primary and secondary servers16
Primary and Secondary Servers…
  • If you use DNS, you will often work with your ISP
  • In a simple environment, the ISP will have the primary and secondary DNS servers
    • You contact them for changes
  • You can also split the servers
    • ISP has primary, you have secondary
    • You have primary, ISP has secondary

Domain Name System

primary and secondary servers17
Primary and Secondary Servers…
  • ISPs maintain DNS
  • You have to send changes to ISP
  • You have the secondary server which gets updates from the primary server
  • Your users reference your secondary server which is faster

Domain Name System

primary and secondary servers18
Primary and Secondary Servers…
  • You have complete control over DNS
  • You can make changes whenever you want
  • If your primary DNS goes down, the secondary will continue to function (but not indefinitely)

Domain Name System

resolve host names
Resolve Host Names
  • Caching Server
    • Resolves host names
    • Caches (saves) the results
    • Automatically installed when DNS is installed
    • No configuration necessary
  • Forwarding Server
    • Caching server that has access to the Internet and forwards traffic from other caching servers

Domain Name System

zones
Zones
  • A zone is a part of the domain namespace
  • For small domains, the domain name represents a single zone
  • For large organizations, subdomains can be divided into separately maintained zones
    • Each zone typically has a separate DNS

Domain Name System

zones21
Zones…
  • Zones must be contiguous
    • admin.devry.edu can be combined with devry.edu
    • admin.devry.edu cannot be combined with student.devry.edu
  • There must be one primary DNS server in each zone (plus a secondary server)
  • Each zone can have multiple secondary DNS servers

Domain Name System

zone file configuration
Zone File Configuration
  • Two ways of DNS resolutions include:
    • Forward Lookup (resolution)
      • These zones contain entries that map names to IP addresses
    • Reverse Lookup (resolution)
      • These zones contain entries that map IP addresses to names

Domain Name System

dns configuration in linux
DNS Configuration in Linux
  • /etc/named.conf describes the files that configure the zones
  • There are two primary files that it describes
    • Forward lookup is described by named.technowidgets.com
      • It has the host names and how to handle e-mail
    • Reverse lookup is described by named.0.168.192
      • Can be necessary for e-mail (SMTP) and security programs

Domain Name System

starting dns in linux
Starting DNS in Linux
  • To start DNS
    • /etc/rc.d/init.d/named start
  • To restart DNS
    • /etc/rc.d/init.d/named restart
  • To stop DNS
    • /etc/rc.d/init.d/named stop
  • Make DNS start when you boot Linux
    • Add the command to start DNS to /etc/rc.d/rc.local

Domain Name System

configuring client dns in linux
Configuring Client DNS in Linux
  • Modify /etc/resolv.conf
  • The following line directs the client to use the DNS server at 192.168.0.100
    • nameserver 192.168.0.100
  • The following line associates this computer with the technowidgets.com domain
    • domain uakron.edu

Domain Name System

test the dns
Test the DNS
  • Configure a Windows PC to use the DNS server
    • Start->Settings->Network Connections
    • Right-click on Local Area Connection and select Properties
    • Select Internet Protocol (TCP/IP) and click on Properties
    • Change DNS to 192.168.0.10
    • Reboot and ping www.technowidgets.com

Domain Name System

name resolution in windows
Name Resolution in Windows
  • NetBios (computer) names are broadcast to the local network
  • The WINS database has computer name to IP address resolution
  • Windows uses Dynamic DNS
    • DNS is required for Active Directory Services

Domain Name System

ad