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Objectives

• Identify the basic components of a network

• Describe the features of Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6)

• Configure clients for IPv4 and IPv6

• Upgrade a network from IPv4 to IPv6

• Troubleshoot Transmission Control Protocol/Internet Protocol on networks

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Introduction to Networking• Basics of networking

– A network is a group of two or more nodes

– Networking is the practice of:

• Designing, implementing, and managing a collection of computers and devices or a network

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Network topology: Physical and logical relationship among devices

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Basic Network Components• Network interface cards (NICs)

• Repeater– Receives a signal & resends at a higher level or power

• Hubs – Have multiple ports to which nodes connect

• Network bridges – Connect one or more network segments

• Switches – Work at Layer 2 of the OSI model and forward frames

between ports based on MAC addresses

• Routers – Forward packets between subnets, or networks– Connected to at least two networks

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Four-Layer Conceptual Model

IP Address

4 Octal (4 Byes) separate by a “dot” between each octalLeading bits are network ID and trailing bits are host IDSubnet mask defines how many bits are network ID and how many bits are host ID

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IPv4 Address

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Exercise: Convert Dotted-Decimal IP Address to Binary 172.16.1.5

27 26 25 24 23 22 21 20

27 26 25 24 23 22 21 20

10101100.00010000.00000001.00000101

Subnet Masks

• 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– 1 AND 1 1– 1 AND 0 0– 0 AND 1 0

Exercise: ANDing• Find the network ID given a subnet mask and IP address

IP Address: 172.16.1.5

Subnet Mask: 255.255.0.0

1. Convert to Binary

172.16.1.5 10101100.00010000.00000001.00000101

255.255.0.0 11111111.11111111.00000000.00000000

2. ANDing11111111.11111111.00000000.00000000

10101100.00010000.00000001.00000101

10101100.00010000.00000000.00000000

Network ID

Host ID

IP Address Class

• Network ID cannot be 127 (loopback)

• ID bits cannot be all “1”s (broadcast)

• ID bits cannot be all “0”s.

• Host ID must be unique.

• IP address of client gateway is the router.

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Subnetting• The process of creating multiple smaller networks, or

subnets, from an IP network address– Take some bit(s) from the host ID and make them as the

network ID– The number of subnets can be calculated with the formula 2n

where n is the number of bits to remove from the host ID

• Classless Interdomain Routing (CIDR)– Uses variable length subnet masks.

• E.g. 18.239.5.3/13 means first 13 bits are network ID

Supernetting• Combining two or more subnetworks into a larger

supernetwork: Take some bit(s) from network ID as host ID

Exercise: Divide the network 172.16.0.0 into 10 smaller networks using the least amount of bits necessary

43 2161082

Need to borrow 4 bits from hose ID

Subnet Mask: 11111111.11111111.11110000.00000000

Convert to Decimal Value

11110000 128 + 64+32+16 =240

Subnet Mask: 255.255.240.0

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Special-Use IPv4 Addresses• Special-use IPv4 addresses

– Mulitcast: 224.0.0.0 to 239.255.255.255– Reserved: 240.0.0.0 to 255.255.255.255– Private IP:

• 10.0.0.0 to 10.255.255.255• 172.16.0.0 to 172.31.255.255 • 192.168.0.0 to 192.168.255.255

– Automatic Private IP Address: 169.254.0.0 to 169.254.255.255

– Loopback: 127.x.x.x

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Introduction to IPv6• IPv6 Advantages:

• Improved security Built-in encryption• Improved autoconfiguration by routers• Simplified routing Neighbor Discovery

• Addressing with IPv6– IPv6 addresses are 128 bits, or 16 bytes, Expressed in 8 groups of 4

hexadecimal digits, separated by colon :– For UNC path, replace : by – and append .ipv6-literal.net

• E.g. \\abcd-12bc-34-1a.ipv6.literal.net\myShare– For URL, enclose IPv6Address in brackets.

• E.g. http://[ff06::45]:443– IPv6 rules for shortening addresses

• Any leading digit of 0 can be dropped from any group• Two or more groups of zeroes can be replaced by two colons (can be

done only once per address)– CIDR notation for subnetting an address

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IPv6 Address Types• IPv6 addresses fall into the following types

– Link-local addresses with prefix of FE80::/64 • Similar to IPv4 APIPA 169.254.0.0/16

• Can NOT be routed

– Unique local addresses with prefix of FD00::/8 • Similar to IPv4 Private IP

• Can only be routed Internally

– Global addresses• Similar to IPv4 Public IP

• First 3 bits are always 001, followed by 45 bits global routing prefix, then followed by 16 bits Internal Subnet ID

• Last 64 bits Interface ID (host ID)

– Multicast addresses with prefix of FF00::/8– Special addresses

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IPv6 Client Configuration

• Autoconfiguration: – 2008 generates Link-Local Address– Then, contacts a local router for Network Configuration

• Stateless: Client generates Global Address

• Stateful: Client accepts ip address from DHCP server

– When no router & DHCP NO Global Address

• DHCPv6– Provide secondary Network Configuration Info. such as

DNS server IP address

• Neighbor Discovery– Used by IPv6 clients for router discovery on a network

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Upgrading Your Network to IPv6• Dual-Layer IP stack

– 2008 uses dual-layer TCP/IP Stack architecture

• IPv6 over IPv4– Encapsulate IPv6 in IPv4

packet– Tunnels that can be created

• Router-to-router• Host-to-router and router-to-

host• Host-to-host

• ISATAP• 6to4• Teredo

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ISATAP• Allows IPv6 routers and hosts to communicate across

IPv4 networks

• Used for two IPv6 hosts communicate through Private IPv4 network

• Requires a router that supports ISATAP

• Interface ID is separated into two parts– First 32 bits are either 0:5efe for a private address or

200:5efe for a public address– Last 32 bits are the IPv4 address

• netsh commandsnetsh interface isatap show state

netsh interface isatap set state enabled

netsh interface isatap set state disabled22

6to4

• Uses tunneling of IPv6 packets over an IPv4 network

• Used for IPv6 companies to connect Internet via IPv4 ISP provider

• Stores the IPv4 address of the ISATAP router in bits 17 to 48

• Encapsulates only the IPv4 router’s IP address, not the destination client

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Teredo• Allows IPv6 hosts to communicate over IPv4

networks that use NAT• Works only with NAT implementations that support

UDP port translation• Should always be implemented with a client-based

stateful firewall• netsh commands to view Teredo status

netsh interface ipv6 show teredo netsh interface teredo show state

• To enable Teredo for workgroup clientsnetsh interface ipv6 set teredo client

• To enable Teredo for Active Directory clientsnetsh interface ipv6 set teredo enterpriseclient

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Disabling IPv6

• For a specific network adapter– You can disable IPv6 using the Network Connections

window and by editing the Registry

• To use the Registry to disable all of IPv6 on a computer, create the following Registry key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TCPIP6\Parameters\ DisabledComponents

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Troubleshooting TCP/IP Networking

• Ipconfig– Displays the current IP configuration on your local client– Ipconfig /all command

• A good way to start troubleshooting clients that have problems accessing network resources

• Ping– Utility that determines whether a target host is on and

responding to communication– Works by sending an ICMP echo request packet to the

target

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Troubleshooting TCP/IP Networking (continued)

• Pathping– Used to map the hops a packet must make to reach a

target

• Tracert– Command-line tool for tracing the route between two

nodes

• Netstat– Command-line tool for displaying network connection

information such as routing tables

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