Domain Name System (DNS) Tutorial

Contents

   1. Domain Name System (DNS)
   2. DNS Components
         2.1 DNS Servers
         2.2 DNS Data Base
         2.3 DNS Client
   3. Prerequisite Steps
         3.1 Static IP Address
         3.2 Steps to Assign Static IP to Server
         3.3 Steps to verify your static IP
   4. Domain Namespace
   5. Zone Types
         5.1 Primary and secondary zones
         5.2 Stub zones
         5.3 Active directory integrated zone
   6. Benefits
         6.1 Multi master replication
         6.2 Stream line data replication
         6.3 Secure dynamic updates
         6.4 Backward compatible to secondary zones
   7. Forward and Reverse look up
   8. Dynamic updates
   9. DNS Records
         9.1 A [Host]:
         9.2 PTR [Pointer]:
         9.3 SOA [Start of Authority]:
         9.4 SRV [Service Locator]:
         9.5 NS [Name Server]:
         9.6 MX [Mail Exchanger]:
         9.7 CNAME [Alias]:
  10.  Zone Transfers:
         10.1 AXFR [Full Transfer]:
         10.2 IXFR [Incremental Transfers]:

Domain Name System (DNS)

DNS stands for Domain Name System, which is basically an internet service to translate (convert) the domain names in to IP addresses as domain names are alphabetic and easy to remember then IP addresses. A distributed database is used to implement and store this name and address information for all public hosts on the internet.

DNS Components

DNS Servers

Responsible for answering queries (Request to translate name and IP addresses).DNS server change domain names to IP addresses and locating the hosting server.

DNS Data Base

Contain information about name and IP addresses where DNS server goes to and looks for the required information (or answer to the request).

DNS Client

It sends the requests to the DNS server and communicates with DNS server for translation of host name to IP address.

Prerequisite Steps:

Static IP Address

Make sure that the server where you want to install DNS is configured with static IP. Whenever you are installing a network service on a server and you have to provide the service to clients you need static IP as you should not be a moving target.

Steps to Assign Static IP to Server

    * Open start menu and Go to Network and sharing center
    * On the left side of the window click on Manage Network Connections
    * Right Click on the given connection and Disable it
    * Now Right click and go to properties of the connection
    * Click on Internet Protocol Version 4(TCP/IP4) and then click the properties
    * Select Radio Button “Use the following IP address” and write the appropriate static IP address in the given text area
    * Now right Click and Enable the Connection

Steps to verify your static IP

    * Go to start menu, and open up Command Prompt as Administrator
    * In the Command Prompt window Type ipconfig  /all
    * Notice the line “DHCP Enabled. No” which means it has static IP configuration

Domain Namespace

Domain Name space is higher archival naming convention used by DNS to locate given host name in the given domain relative to domain tree. It based on levels that are

    * Root- Domain
    * Top- Level Domain
    * Second- Level Domain
    * Sub –Domain

Zone Types

Zones come in a two different types.
Primary and secondary zones

Primary and secondary are standard zone types. This is how DNS used to work. It still can work same way but it is not common any more.

    * Primary
          o Master
          o Read/write
          o Primary is the master read write copy of the zone. Whatever server is hosting the primary zone will have the master read/write copy of the zone data base coy of the hard drive.
    * Secondary
          o Read only
          o A DNS server hosting a secondary zone has a read only copy of the database. So no changes can be made. It has the full database it can respond to client requests and it is used for the exact purpose but updates cannot be made.
    * Stub
          o Only contains information about other DNS servers.
          o A stub zone only contains information about other DNS servers. It does not have a full database.
    * Active Directory Integrated
          o DNS database is stored as an active directory object.
          o Active directory integrated zones take the place of all primary and secondary. Now the DNS database is stored as an active directory object eliminating that master read/write copy having a single master. Now we can use the multi master topology that active directory provide for us.

Stub zones

    * DNS allows for delegations.
    * A delegation is where another DNS server has been delegated the authority over a sub-domain.
    * Before stub zones, all delegations had to be managed manually.
    * A stub zone allows for the automatic propagation of delegation to DNS servers.

Active directory integrated zone

Active directory integrated zone has many benefits.

Benefits

    *  Multi master replication
    *  Stream line data replication
          o Now we have DNS and active directory databases together and replicate them altogether as one.

    *  Secure dynamic updates
          o Dynamic updates can now be secure to have only clients that have been authorized by the active directory database can update the DNS server, which stop somebody generically out of the internet for updating your DNS server.
*    Backward compatible to secondary zones
          o In active directory integrated zone will act as a primary zone. If you have older DNS server or UNIX bind DNS server which you want to keep functioning but it does not have the mechanism to support active directory integration. Simply make old DNS server in to a secondary zone DNS server pointing to one of the active directory integrated DNS servers as its primary and everything will work just fine.

Forward and Reverse look up

    * Forward look up
          o Name to IP address
          o Widely used
    * Reverse Look up
          o IP address to name
          o Not always needed
          o Usually used to meet the needs of a particular application (very often for validation purposes)

]Dynamic updates

    * Before dynamic updates all DNS information was manually entered.
    * Now records can be dynamically added (or updated) from the client.
    * Updates can be secured with active directory integrated zones. (Authorized users)
    * Dynamic updates can be integrated with other network services. (I.e. DHCP).
          o DHCP inform DNS to make a record that an IP address has been given.

DNS Records

The record can be added to the zone files we create. With the help of standard DNS query the DNS Resolver class resolves the domain names.As a result of the DNS query there is a DNS response that contains the DNS record for that query. And this DNS record contains the information depending upon the type of DNS resource record. There are many DNS record of different types but some of the records are commonly used. These are following:

A [Host]:

The A record or Host record resolves the Host name in to IP addresses and it is a typical Forward Lookup Record.  And A Record maps an IPv4 address to a hostname.

PTR [Pointer]:

The PTR or Pointer Record resolves the IP addresses to a Host name and it is exactly opposite to the A or Host Record and also called a Reverse Lookup Record

SOA [Start of Authority]:

This is the first record in any zone file and it is most authoritative for the zone.It gives the foundation and the starting point for the zone database. The SOA Record is added automatically created when we add a zone.

SRV [Service Locator]:

SRV Service Locator Records are used to represent a certain service that a computer is may be offering. They are typically use in conjunction with active directory.Active Directory requires DNS in order for its clients to locate the presence of domain controllers. When a user attempts to login for instance the client machine go out to its DNS Server to find the domain controller for the particular domain. It is the SRV Resource Record that resolves the query and directs it towards the domain controller services for that particular domain. The A record works in correspondence with the SRV Record to resolve the hostname in to IP addresses.

NS [Name Server]:

The Name Server or NS Record identifies the DNS Servers that are authoritative in each zone. And it specifies a name server for the particular domain that allows the DNS lookups within the different zones in the domain.

MX [Mail Exchanger]:

The MX or Mail Exchanger Record is used to help email give from one point to another suppose when you want to send an email to some body at sbk.edu.pk there are the DNS server over the internet that have MX or Mail Exchanger Record which point to our Email server. The Mail Exchanger Record specifies a mail exchange server for the particular domain that allows the mails to deliver to that particular mail server in the domain.

CNAME [Alias]:

The CNameor Canonical Name or simply refers to Alias some times. The CNAME Record resolves the Alias to a host name. For example when you go to www.microsoft .com then now the Microsoft might have the web server named webserv1.microsoft.com.when any body types www.microsoft .com the CNAME Record has been actually created where www.microsoft.com is directed to webserver1.microsoft.com.

Zone Transfers:

Zone transfers are only used with the Standard zones that are Primary and Secondary Zones. They cannot use with Active Directory Integrated zone. Replication takes place in active directory integrated zone as part of active directory replication. When we use standard zones Primary or Secondary we use Zone Transfers for this replication. There are two different types of zone transfers

AXFR [Full Transfer]:

AXFR means transfer the entire database. Older version of DNS has to do it every time there is an update. AXFR is really only used when we first create a secondary zone to get the entire database to come over or for the recovery of database.

IXFR [Incremental Transfers]:

IXFR is used to for the incremental transfers and most commonly used now days. IXFR is used to save our bandwidth so that when changes made only that changes must be added to the secondary.

Note: The DNS Zone Transfers can be a Security risk as there are number of issues surrounding zone transfers for example a hacker might be able to create the DNS Server and can tell your primary database that it is the secondary database through all the data here. Zone transfers are less secured then the Active Directory Integration.

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Active Directory Domain Services (ADDS) Tutorial

Contents

1 Directory:

2 Active Directory:

3 Active Directory Domain Services (ADDS):

4 Rules and Features in Active Directory Domain Services:

5 Benefits of Active Directory Domain Services:

6 Important Terms, Tools and Concepts in AD DS:

6.1 FQDN (Fully Qualified domain Name):

6.2 Active Directory Users and Computers:

6.3 User:

6.4 OU (Organizational Unit):

6.5 Group Policy Object (GPO):

7 Benefits of using GPO

8 Roaming Profile

9 The Issues with Roaming Profile:

10 Network Drive (Z drive)

11 Advantages Network Drive:

12 Home Directory/ Home Folder:

13 Assigning Home Folder:

ACTIVE DIRECTORY DOMAIN SERVICES (ADDS)

Active directory was introduces on 1990’s and implemented in Windows 2000 Server with its release in 2000. Windows Server 2003 and Windows Server 2008 used Active Directory with its expansions during time. Window 2000 Server, Windows Server 2003 and Windows Server 2008 use Active Directory domain Services as a base for distributed networks (distributed computing network system).

Directory:

The listing of objects in the comprehensive way general data base of information or repository is known as directory.

Active Directory:

Active directory provides a way to store and avail information related to the network objects to other users, administrator and applications. The objects organized inform of organizational units (OUs), domain, sites, trees and forests. Active directory with the standard protocols is accessible by third party directory services because it can easily exchange and use the information effectively.
Active Directory in Windows Server 2008 R2 with the expand functionalities provide centralized administration to its users and application objects. The management of related identities are provided for the network of organization by Active Directory.

Active Directory Domain Services (ADDS):

The Active directory domain Services stores information and use stored data in the computer network. It has hierarchal structure for network objects. Objects include in the network are users, resources, computer accounts, security policies and applications. The user account in the Active directory can stores names, email address and password which are the example of particular information stores in the directory. Active Directory Domain Services make the server domain controller and it is integrated with Domain Name system (DNS).The data is protected from unauthorized use and access of objects by any unauthorized access. The integration of AD DS with operating system and other applications has different capabilities like shared resource management. AD DS provides easier access of data for the users and administrator.

Rules and Features in Active Directory Domain Services:

The following features are included in Active Directory domain Services

• Access control to resources and authenticated logon for the users for the security integration in AD DS
• Central management and organization by administrator with single network logon
• The specific formats and limits for the objects and their related attributes
• The use of global catalogue by the users and administrator for information about the objects
• Index mechanism provide query system for the easy access of network objects and their attributes
• Centralized management of network with the security
• Comprehensive use of network object and properties with protected management

Benefits of Active Directory Domain Services:

Active Directory Domain Services is very secure with the comprehensive solution for the span network in multiple locations.

• Ease of administration with centralized secure management
• Comprehensive management with the increasing number of objects (users, computers and roles)
• Provide single view of the users with proper management
• Single network with different mechanisms of security
• Automation for the administration tasks like managing and adding users and groups or other works related to different objects

Important Terms, Tools and Concepts in AD DS:

FQDN (Fully Qualified domain Name):

The FQDN is specified for the host, internet or specific computer. It is the complete name with two parts host name and domain name and also top level domain. Like project.sbk.com is FQDN where project is host name, “sbk” is second level domain and com is top level domain. FQDN has specific location in the hierarchy of Domain Name System (DNS).

Active Directory Users and Computers:

The active Directory Users and Computers is tool and a console snaps in introduced by Microsoft for the management purposes. You can create user and computer accounts; set their security policies an2d you can also apply group policies.

User:

User is the person who can use any specific computer in the given environment with the specified policies. You can log on the computer by the Active Directory user account. The Active Directory account identifies the user and establish authentication so that the user can use the resources within the domain.

OU (Organizational Unit):

Organizational Unit let you organize the users in one container that can hold all user and computer accounts that have common needs so that can be easily managed and supported by the administrator. The example is an OU Students that is for all the common users. The domain can contain the collection of different OUs with the same policies like security (password policy) that is basically same for every user in the OU. The organizational unit administrator is responsible for user and computer account maintenance in the OU.

Group Policy Object (GPO):

Group policy object is the tool which provides centralized configuration and management for the operating system and let you set rules on user and computer accounts in the Active Directory as the system administrator. It is used in the small businesses and organizations very commonly. Group policy object will store the configured setting of Active Directory. The management and configuration of software, desktop and network environments can be done by GPO. The Group Policy is the feature in Windows Server 2008’s Server Manager you need to install so that you could use and manage multiple accounts. Group Policy management console let you easily use different policies for the group policy objects.

Benefits of using GPO

There are some uses of Group Policy Objects

• You can block as the administrator the devices for specific users
• The improved security implementations for devices and users using firewall and IPsec
• Categorized management of resources makes it possible to easily deploy and manage the resources
• You can manage multiple groups, logs and event in the GPO

Roaming Profile

The roaming profile let you store and access the shared documents and desktop setting on the same network with the customize settings seamlessly. The roaming profile stores your customized data on the server; you can get access of your profile data in the same way as you saved last time even using the other computers on the network so roaming profile makes it possible by just joining the domain regardless of location. Administrator can control and designate the roaming profile to the domain administrator group and other groups and accounts.

The Issues with Roaming Profile:

The roaming profile bandwidth problems can appear inform of time consuming logging in and logging off from the account. The transformation and use of higher bytes of data is not possible with it and it can create problems for the different accounts of the users log in at the same time.

Network Drive (Z drive)

Network drive is the shared space on the hard disk for different users in the network. It is a central location for the users provided on the server also known as remote drive. The data from here is accessible by the authorized users of the domain. Mapping the network drive can be the time saver to access data files and folders from remote computer (Server). The path of drive is specified for each user in the network so the users can easily access their required data.

Advantages Network Drive:

Network drive has the following benefits:

• A user do not need to follow and remember a large path to access the data, you just need to open ‘‘My Computer’’ and the access allocated drive by the administrator
• You do not need to shift and transfer data after each modification, your data is save at your network drive
• In case of any problem in the client computer data is accessible in the centralized domain controller or server

Home Directory/ Home Folder:

Home directory is used for the user so that they can save securely their data and could easily access the data. The users can have their unique and individual home directory to save and use data. The UNC (Universal Naming Convention) path is used and you can access your home drive from any directory. The users can save the images, music, videos and text document in the home drive. In command line activities it is called home directory and in graphical user interface it is known as home folder. The user profile is used as the default home folder for the user accounts. It has following benefits:

• Provide backup of important data on the server central to separate users by the administrator
• Central collection of files makes the management easier for the administrator
• Secure data by providing separating system data and user’s data, and providing recovery to data
• The large files can be store easily
• The user can access the data from any connected computer in the network

Assigning Home Folder:

You can assign home folder to the domain users easily by the following the instructions.

• Home folder path should be specified
• The shared permissions should permit the user to access the home folder
• Assign the home folder to the domain user

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Installation and Configuration of DNS on Windows Server 2008

Installation and Configuration of DNS

• Go to the Start Menu and select Server Manager

  

• The Server Manager Console will be open select Add Roles from Right pane

  

• The Add Roles Wizard will be open click Next

  

• Select The DNS Server Role from the Roles list and click Next

  

• Read the introduction to DNS Server and Click Next

  

• Review the Confirm Installation Selection and click Install

  

• Check the Installation Progress

  

• When the installation is succeeded click close to exit the installation wizard.

  

Configuration of DNS Zones

• Click on the Start menu select Administrative Tools and choose DNS to open DNS Manager Console

  

• The DNS Manager Console will be open, now expand your computer name

  

• Right Click on Forward Look up Zones and select New Zone from the list

  

• On the New Zone Wizard click Next to continue

  

• Choose Primary Zone for creating the primary forward look up zone and click the check box for storing the zone in Active Directory and click Next.

  

• Select To all DNS servers in this domain: project.cs.com (your domain name) and click Next

  

• Give appropriate Zone Name and click Next

  

• Select the radio button to Allow Secure Dynamic Updates and click Next

  

• Review the Settings you specified and click Finish

  

• The newly created zone (sbk_zone) is displayed under the forward look up zones

  

Thank you…………

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