NW_WK2 - carrieclasses

cursefarmΔίκτυα και Επικοινωνίες

24 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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1

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

2


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

3

4

Network topology:
Physical and logical relationship among
devices

5


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

6

Four
-
Layer Conceptual Model

8

IPv4 Address


IPv4


Uses unique 32
-
bit (4
-
byte) addresses


Each byte is called Octet

9


Subnetting


The process of creating multiple smaller networks, or
subnets, from an IP network address


Subnet mask


Can determine the network and host ID portions of an
IP address


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.

11


Subnetting (continued)


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


Classless Interdomain Routing (CIDR)


Uses variable length subnet masks.


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


Supernetting


Combine two or more subnetworks into a larger supernetwork


12



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

13


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

14

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

15

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


16

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 commands


netsh interface isatap show state


netsh interface isatap set state enabled


netsh interface isatap set state disabled

17

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


18

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 clients


netsh interface ipv6 set teredo client


To enable Teredo for Active Directory clients


netsh interface ipv6 set teredo
enterpriseclient

19

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
\
CurrentControlSe
t
\
Services
\
TCPIP6
\
Parameters
\

DisabledComponents

20

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

21

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

22