Chapter 2: Configuring Network Protocols

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Oct 27, 2013 (3 years and 7 months ago)

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70
-
291:

MCSE Guide to
Managing a Microsoft Windows
Server 2003 Network



Chapter 2: Configuring
Network Protocols




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291: MCSE Guide to Managing a Microsoft Windows Server Network

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Objectives


Understand TCP/IP addressing


Define TCP/IP parameters


Configure TCP/IP parameters


Work with TCP/IP networks


Understand the process of subnetting a TCP/IP
network


Supernet several smaller networks


Configure other network protocols


Use bindings to optimize network connectivity



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Overview of TCP/IP


Most commonly used network protocol today


Has wide vendor support


Open protocol


Provides access to the Internet


Windows has been designed so that many of its
features require TCP/IP

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Defining TCP/IP Parameters


To participate on a TCP/IP network, your computer
must have a valid Internet Protocol (IP) address and
subnet mask


Optionally, you may configure gateway, DNS, or
WINS information

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IP Addresses


An IP address:


Unique number assigned to the computer that identifies
itself on the network


Unicast involves directed communication between
two single computers using TCP/IP


Consists of four octets


Composed of network and host IDs


Only computers with the same network ID can
communicate without the assistance of a router

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IP Addresses (continued)


ICANN has the overall authority over IP address
assignments


If the network is not connected to the Internet, the
choice of IP address is entirely up to the network
administrator


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Subnet Masks


Subnet masks are used to define which part of an IP
address is the host ID and which part is the network
ID


Like an IP address, it is composed of four octets


The simplest subnet masks use only the values 0 and
255


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Subnet Masks (continued)


A computer uses the subnet mask and IP address to
determine its network ID


In order to communicate, two machines must be on
the same network


Before sending a packet over the network, the
computer will check to see if the destination address
is on the same network

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Default Gateway


Another term for a router


If a computer does not know how to deliver a packet,
it sends the packet to the default gateway


A router may be a dedicated hardware device or a
computer with multiple network cards


The router must be on the same network as the
computer sending the packet


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DNS


Essential to a Windows Server 2003 network


Resolves host names to IP addresses


Used to find domain controllers


Used to find Internet resources such as Web servers
or e
-
mail servers


Domain names must conform to a hierarchical
naming scheme called DNS namespace of BIND

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Configuring TCP/IP Parameters


A static IP configuration is one in which the IP
address of the machine is specified manually by the
administrator


DHCP performs the task of assigning IP addresses to
machines automatically


The network 169.254.0.0 is reserved for Automatic
Private Addressing


An address in the above range is generated if a DHCP
server cannot be reached


An address in the above range is not routable

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Working with TCP/IP Networks


Before working with TCP/IP networks, one must
have a basic knowledge of:


IP address classes


Classless inter
-
domain routing


Reserved addresses

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IP Address Classes


IP addresses are divided into classes


This class defines the default subnet mask of the
device using the address


All classes can be identified using the first octet of
the IP address


The classes are denoted A through E


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IP Address Classes (continued)

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IP Address Classes (continued)


Class A

has only 127 potential networks but
16,777,214 potential hosts


Class B

provides for 16,384 networks and 65,534
hosts


Class C

provides for 2,097,152 networks and 254
hosts


Class D

IP addresses cannot be assigned to computers
and are used for multicasting


Class E

IP addresses are not used and considered
experimental

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Classless Inter
-
domain Routing


At one time, IP address classes were used by routers
on the Internet to move packets


To improve efficiency, classless inter
-
domain routing
was adopted


Does not use the default subnet masks for routing


Subnet masks must be defined for each network

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Reserved Addresses


A number of IP addresses and networks are reserved
for special purposes


A local broadcast uses the IP address
255.255.255.255


A directed broadcast uses the IP address obtained
through the destination network ID and all host ID
bits set to 1


Any IP address with the first octet set to 127 cannot
be assigned to a host


These addresses are called loopback addresses

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Subnetting TCP/IP Networks


Subnetting involves separating a larger network into
smaller networks to increase efficiency


Reduces collisions


Limits broadcasts


Controls traffic


A router is required to move packets between subnets

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Reducing Collisions


A collision occurs when two computers attempt to
transmit data at the same time


Subnetting reduces the number of hosts on a network


Therefore reduces the amount of traffic on that network


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Limiting Broadcasts


Broadcast messages are generated by such services as
NetBIOS name resolution, router communication,
and service advertisements


A packet that is broadcasted is read and processed by
every computer on the network


Subnetting reduces the number of hosts on each
network


Results in fewer broadcasts for each network


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Controlling Traffic


Introducing routers over a network gives you more
control over network traffic


Most routers have the ability to control which packets
are forwarded


IP addresses are represented in dotted decimal format
but are handled by computers in binary format


Subnetting is based on binary numbers


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Conversion between Binary and
Decimal


Binary digits are always one or zero


Each octet in an IP address is converted to binary by
the machine


Windows calculator will perform the conversion
between binary and decimal for you


The conversion process simply involves changing the
number system between base 10 and base 2

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Working with Binary IP
Addresses and Subnet Masks


Subnet masks are represented in the dotted decimal
format but handled in binary by computers


1 in the subnet mask indicates that the corresponding
bit in the IP address is part of the network ID


0 in the subnet mask indicates that the corresponding
bit in the IP address is part of the host ID


ANDing:


Process used to separate network and host IDs from an IP
address

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Creating Subnets


To subnet a network, take some bits from the host ID
and give them to the network ID


For simplicity, bits are taken from host ID in groups
of eight


A class B address is very large and typically needs to
be subnetted


Complex subnetting involves taking less than a full
octet from the host ID


The number of subnets can be calculated with the
formula 2n
-
2 where n is the number of bits to remove
from the host ID



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Supernetting TCP/IP Networks


Supernetting is the opposite of subnetting


Used to create a larger network from multiple smaller
ones


Takes bits from the network ID and gives them to the
host ID


All networks being combined must be contiguous


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Reasons for Supernetting


Supernetting is used when a range of IP addresses
larger than a class C network is required but a full
class B network is not required


May also be done to decrease routing complexity by
replacing multiple networks with routers into a
supernetted network with switches



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Configuring Other Protocols


IPX/SPX


NWLink


Appletalk


Data Link Control


NetBEUI

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IPX/SPX


The most common protocol in use for LANs in the
late 1980s and early 1990s


Less common now that TCP/IP was introduced


Movement away from IPX/SPX was due to the
gaining popularity of the Internet


NetWare, a popular network operating system at the
time, required this protocol

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IPX/SPX (continued)


IPX/SPX uses Service Advertising Protocol to locate
services


Packets consist of a network and computer ID


Network ID is an 8
-
character hex number and the
computer ID is a 12
-
character hex number


No subnet masks are necessary (fixed lengths)


Configure Server 2003 with an internal network
address other than basic file and print services

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IPX/SPX (continued)


Has multiple frame types


A frame is a fully assembled packet just before being
placed on a network


Computers configured with different frame types
cannot communicate


The ipxroute config command will tell you the
current IPX configuration

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AppleTalk


This protocol is used to provide connectivity for
Macintosh computers


Windows Server 2003 can emulate a Macintosh file
or print server


There is no need to install the protocol if Macintosh
computers are not connected on the network


AppleTalk is routable and can be used on larger
networks

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Obsolete Protocols


Several protocols were available in older versions of
Windows and are not available in Windows Server
2003


Data Link Control is a nonroutable protocol that was
used to connect mainframe computers


NetBEUI was one of the most popular protocols for
early Windows networks


Fast


Nonroutable


Can be autoconfigured

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Configuring Protocol Bindings


Binding is a process where a network protocol is
configured to use a network adapter


Windows Server 2003 allows specifying the ordering
in which protocols are used


For each adapter, you can specify which clients and
services are bound


You can also specify which network protocols are
bound to each client or service


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Summary


Windows Server 2003 uses TCP/IP as its primary
networking protocol


There are several ranges of IP addresses reserved for
internal use and are not routable on the Internet


DHCP is used to automatically allocate IP addresses
and other IP configuration information to clients


If a DHCP server cannot be contacted, then clients
use APIPA


Subnetting divides a single large network into
multiple smaller networks


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Summary (continued)


Computers work with IP addresses as 32
-
bit numbers


A 1 is a bit that is part of the network ID. A 0 is to a
bit that is part of the host ID


Subnetting takes bits from the host ID and uses them
as part of the network ID


The formula 2
n


2, where
n
is the number of host
bits, calculates the number of useable hosts


Supernetting combines multiple smaller networks
into a single larger network

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Summary (continued)


The IPX/SPX protocol can be used with the 32
-
bit
version of Windows Server 2003; primarily used in
networks where Novell NetWare is present


The AppleTalk protocol is available for Windows
Server 2003; used for connectivity with Apple
Macintosh computers


Bindings can be adjusted to optimize performance


Most
-
used protocols should be listed first