NT1330 Client Server Networking 2

UNIT 2Configuring and Maintaining

the DHCP and DNS Server Roles

Class Agenda 12/16/15• Learning Objectives• Lesson Presentation and Discussions.• Lab Activities will be performed in

class.• Assignments will be given in class. • Break Times. 10 Minutes break in

every 1 Hour.• Assignment and labs are posted to

the website.• http://obinkyerehclassess.weebly.com

Skills MatrixTechnology Skill Objective Domain Objective #Configuring the DHCP Server Role

Configure Dynamic Host Configuration Protocol (DHCP)

1.2

The DHCP Server Role• Each host must have an Internet Protocol

(IP) address and a subnet mask, and if communicating outside the local subnet, each must also have a default gateway.

• Each IP address must be valid and unique within the host’s internetwork.

• Manually managing IP addresses is a complex tedious task.

• The Dynamic Host Configuration Protocol (DHCP) simplifies this process by automating the assigning, tracking, and reassigning of IP addresses.

Dynamic Host Configuration Protocol (DHCP)

• DHCP can dynamically allocate an IP address from a pool of addresses and then reclaim it when it is no longer needed.

• Because this process is dynamic, no duplicate addresses are assigned by a properly configured DHCP server, and administrators can move computers between subnets without manually configuring them.

Benefits of the DHCP• Four Key benefits to DHCP:

– Centralized administration of IP configuration.

– Dynamic host configuration.– Seamless IP host configuration.– Flexibility and scalability.

DHCP Messages• All DHCP messages are carried in

User Datagram Protocol (UDP) datagrams using the well-known port numbers 67 (from the server) and 68 (to the client).

• UDP operates at the Transport Layer of the OSI model and is a low-overhead protocol because it does not use any type of packet acknowledgement.

DHCP Messages

DHCP Lease Renewal

DHCP Relay Agent

Automatic Private IP Addressing (APIPA)• If the DHCP client is unable to locate a

DHCP server and is not configured with an alternate configuration, the computer configures itself with a 169.254.0.0/255.255.0.0 address.

• The auto-configured computer then tests to verify that the IP address it has chosen is not already in use by using a gratuitous ARP broadcast.

• If the chosen IP address is in use, the computer randomly selects another address. The computer makes up to 10 attempts to find an available IP address.

Installing the DHCP Server Role• Adding the DHCP server role is

largely wizard-driven via the Server Manager console and allows you to configure basic DHCP settings at the same time that you install the role.

• To add DHCP Server Role on a Server Core Installation of Windows Server 2008, use the following command:

Start /w ocsetup DHCPServerCore

Practical Activity : Installing DHCP server role on Server 2008

• Student will take 15 minutes to follow instructions from the text book to install the DHCP

Authorizing a DHCP Server• In implementations of DHCP prior to

Windows 2000, any user could create a DHCP server on the network, an action that could lead to conflicts in IP address assignments.

• In Windows Server 2000 and later, an unauthorized DHCP server (also referred to as a rogue DHCP server) is simply a DHCP server that has not been explicitly listed in the Active Directory Domain Service as an authorized server.

• You must authorize a DHCP server in Active Directory before the server can issue leases to DHCP clients.

Authorizing a DHCP Server• Press Ctrl+Alt+Delete on the Windows

Server 2008 computer. • In the DHCP console, right-click DHCP and

then click Manage Authorized Servers.• In the Manage Authorized Servers dialog

box, select Authorize.• In the Authorize DHCP Server dialog box,

key the name or IP address of the DHCP server to be authorized and then click OK.

• The computer will list the IP and full computer name and then ask for confirmation. – Click OK to continue.

Practical Activity: Authorize a DHCP Server.

• Students will follow instruction to Authorize DHCP Server

DHCP Scope• Determines which IP addresses are

allocated to clients. • Defines a set of IP addresses and

associated configuration information that can be supplied to a DHCP client.

• A scope must be defined and activated before DHCP clients can use the DHCP server for dynamic TCP/IP configuration.

• You can configure as many scopes on a DHCP server as needed for your network environment.

DHCP Scope• The IP addresses defined in a DHCP

scope must be contiguous and are associated with a subnet mask. – If the addresses you want to assign

are not contiguous, you must create a scope encompassing all the addresses you want to assign and then exclude specific addresses or address ranges from the scope.

– You can create only one scope per subnet on a single DHCP server.

DHCP Scope

Available Address Pool• Once a DHCP scope is defined and

exclusion ranges are applied, the remaining addresses form what is called an available address pool within the scope.

• Pooled addresses can then be dynamically assigned to DHCP clients on the network.

Practical Activity: Configuration of DHCP scope• Follow instruction in the book to

configure the DHCP Scope

DHCP Options• DHCP options are additional client-

configuration parameters that a DHCP server can assign when serving leases to DHCP clients.

• DHCP options are configured using the DHCP console and can apply to scopes and reservations.

DHCP Options

Configuring and Managing the DNS Server Role

Lesson 4

Skills MatrixTechnology Skill Objective Domain Objective #Installing the DNS Server Role

Configure a Domain Name System (DNS) server

2.1

Introducing DNS Zones Configure DNS zones 2.2

Configuring DNS Resource Records

Configure DNS records 2.3

Configuring Active DirectoryIntegrated Zones

Configure DNS replication

2.4

Introducing the DNS Name Resolution Process

Configure name resolution for client

2.5

Domain Name System (DNS)• Because DNS plays such a key role in

Windows Server 2008.• Without DNS, your network will most

likely not function — clients won’t be able to resolve names to Internet Protocol (IP) addresses.

• In addition, Active Directory clients use DNS to locate domain controllers.

HOST file• Before DNS, name resolution was

handled through the use of text files called HOSTS files that were stored locally on each computer.

• The HOSTS file listed each name of the host and its corresponding IP address.

• Whenever a new host was added to the network, an administrator would manually update the HOSTS file with the new host name or IP address information.

Domain Name System• DNS because of the following

benefits:– Scalability– Constancy– Ease of Use– Simplicity

DNS Namespaces• A DNS namespace is a hierarchical,

tree-structured list of DNS host names, starting at an unnamed root that is used for all DNS operations.

• Each domain can have additional child domains.

DNS Namespaces

Fully Qualified Domain Name (FQDN)• DNS uses the fully qualified domain

name (FQDN) to map a host name to an IP address.

• An FQDN describes the exact relationship between a host and its DNS domain.

DNS Server Types• DNS server types are determined by

the type of zone or zones they host and by the functions they perform.

• A DNS server may host either primary or secondary zones or both.

• If the server doesn’t host any zones, it is referred to a caching-only server.

• A server is said to be authoritative for a particular zone if it hosts a primary or secondary zone for a particular DNS domain.

Primary Name Server• Primary name servers have been

configured with one or more primary DNS zones.

• When a change is made to the zone data, such as adding resource records to the zone, the changes must be made on the primary server for that zone; these changes will then propagate to secondary name servers.

Secondary Name Server• A secondary name server hosts one

or more secondary zone databases. • Because a zone transfer is used to

create a secondary zone, the primary name server and zone already must exist to create a secondary name server.

Caching-Only Server• Caching-only servers do not host any

zones and are not authoritative for any domain.

• Caching-only DNS servers start with an empty cache and then add resource record entries as the server fulfills client requests.

• This information is then available from its cache when answering subsequent client queries.

• A caching-only DNS server is valuable at a site when DNS functionality is needed locally but when creating a separate domain or zone is not desirable.

AD-Integrated Zones• Zones are stored in Active Directory.• No distinction between primary and

secondary servers.• Changes made on one DNS server

are replicated to other DNS Server.

Installing the DNS Server Role• Before you can use DNS Server Role,

you must install it with Server Manger.

Zones• DNS hierarchical structure is that

workload for name resolution is distributed across many different resources.

• For administrative purposes, DNS domains can be organized into zones.

• A zone is a collection of host name–to–IP address mappings for hosts in a contiguous portion of the DNS namespace.

Zones• Zone data is maintained on a DNS

name server and is stored in one of two ways:– As a text-based zone file containing

lists of mappings, called a standard zone or a file-backed zone.

– Within an Active Directory database, called an Active Directory–integrated zone.

Standard Primary Zone• A standard primary zone hosts a

read/write copy of the DNS zone in which resource records are created and managed.

• Only one server can host and load the master copy of the zone.– no additional primary servers for the

zone are permitted, and only the server hosting the primary zone is allowed to accept dynamic updates and process zone changes.

Standard Secondary Zone• A copy of the zone file may be stored on

one or more servers to balance network load, provide fault tolerance, or avoid forcing queries across a slow, wide area network (WAN) link.

• This standard secondary zone is a read-only copy of the standard primary DNS zone.

• Information from a primary zone is transmitted to a secondary zone by performing a zone transfer, which is done by copying the zone file from the primary server to a secondary server.

Forward Lookup Zone• Most queries sent to a DNS server

are forward queries.– They request an IP address based on

a DNS name. Includes Host (A) resource records that translate form host name to IP address.

Reverse Lookup Zone• The Reverse Lookup zone is in-

addr.arpa domain.• Enables a host to determine another

host’s name based on its IP address.– Contains the Pointer (PTR) resource

record that translates from IP addresses to host names.

Resource Records• The resource record is the fundamental

data storage unit in all DNS servers.– Start of Authority (SOA)– Name Server (NS)– Host (A)– Host (AAAA)– Canonical Name (CNAME)– Mail Exchanger (MX)– Pointer (PTR)– Service Record (SRV)

Start of Authority (SOA) Resource Records• Identifies which name server is the

authoritative source of information for data within this domain. – The first record in the zone database

file must be an SOA record. In the Windows Server 2008 DNS server, SOA records are created automatically with default values when you create a new zone.

Name Server (NS) Resource Records• Identifies the name server that is the

authority for the particular zone or domain; that is, the server that can provide an authoritative name-to-IP address mapping for a zone or domain.

Name Server (NS) Resource Records

A and AAAA Resource Records• The A resource record is the

fundamental data unit of the DNS that is used to translate the host name to the IPv4 address.

• The AAAA resource record is used to translate the host name to the IPv6 address.

• The Pointer (PTR) resource record is the functional opposite of the A record, providing an IP address-to-name mapping, which is found in the reverse lookup zones.

A and AAAA Resource Records

Canonical Name (CNAME) Resource Record• Sometimes called an Alias record, is

used to specify an alternative name for the system specified in the Name field.

Canonical Name (CNAME) Resource Record

Mail Exchanger (MX) Resource Records• Identifies the email servers for a

domain.

Mail Exchanger (MX) Resource Records

Service Record (SRV)• Enables clients to locate servers that

are providing a particular service. – Windows Server 2008 Active

Directory clients rely on the SRV record to locate the domain controllers they need to validate logon requests.

Iterative Query

Recursive Query

Dnscmd Command• You can use the Dnscmd command-

line tool to perform most of the tasks that you can do from the DNS console.

• This tool can be used to script batch files, to help automate the management and updates of existing DNS server configurations, or to perform setup and configuration of DNS servers.

Using NsLookup

Using NsLookup

Advanced DNS Server Properties• Advanced DNS server properties

refer to the settings that can be configured in the Advanced tab of the DNS Server Properties dialog box.

• These properties relate to server-specific features, such as disabling recursion, handling resolution of multi-homed hosts, and achieving compatibility with non-Microsoft DNS servers.

Unit 2 Lab 2• Unit 2. Lab 1. Configuring DNS and

DHCP

Unit 2 Assignments• Unit 2. Assignment 1. DHCP

Troubleshooting• Unit 2. Assignement 2. DNS Scenario• Unit 2. Assignment 3. Windows 2008

Network Services