network addressing

Network AddressingNetworking for Home & Small Business

Objectives

Purpose of an IP Address

• Each host needs IP to communicate

• Assigned to the NIC– Computers, network printer, router interfaces

• Remember– Packet has source & destination IP

Everything is IP

IP Address Facts

• Logical (not physical like MAC)

• IPv4

• 32 bits, 4 octets– 8 bits in each octet– 11111111.10101010.11001100.00100101

• Written in decimal– 192.101.28.36

• Value in each octet from 0-255– That’s a total of 256 numbers.

Convert binary to decimal

• Add up the values of the binary 1’s

• 128 6432 16 8 4 2 1

• 1 0 0 1 1 1 0 0– 156

• 11100101– 229

Binary/Decimal Conversions

• Practice

• Binary Game

• Handout

Parts of an IP Address• Network portion• Host portion

• Routers care about network portion

• 192.175.36.9

Activity

IP & Subnet Mask

• Subnet Mask– Helps router decide which network packet is on– Helps show which part of IP is network & host– 32 bits– 192.168.6.5 255.255.255.0

• Binary 1’s - ID the network portion

• Binary 0’s - ID the host portion

What network are these on?

How many hosts- Unsubnetted?

• SM helps tells us how many hosts are on that network– 255.255.255.0– Binary 0= identifies # of hosts on that network

• How many total hosts can be in one octet?– 256– Subtract 2 for useable

• 00000000 (.0) is the network ID• 11111111 (.255) is the broadcast address for a

network

Binary/Dec/Hex

• Hex= MAC address

• 0-9, A-F (10-15)

• AB

Handout & Lab

• 5.1.4 Lab

• Homework

Review

1. Which version IP addresses are we dealing with?

– IPv4

2. How many bits in an IP address?– 32

3. How many octets in an IP address?– 4

4. Which part of this address is the host portion? 199.81.71.6

– 6

Review

1. Which network does this belong on? 201.14.6.5 255.255.255.0

– 201.14.6.0 network

2. How many total hosts can be on that network? Useable?

– 256– 254, why?

IP Classes & Default SM

• Class A– Large organizations– 1-127– Default SM= 255.0.0.0

• One octet for network, 3 octets for hosts

– How many hosts available?• 224= over 16 million

– 10.52.33.7– N.H.H.H– 255.0.0.0– 120.111.99.87

Class A Example

• 15.7.92.5 255.0.0.0

• 15= Class A• Default SM for Class A= 255.0.0.0• Network portion of address= 15.• Host portion= .7.92.5• Network ID= 15.0.0.0

– All zero’s in the host portion

• Broadcast address= 15.255.255.255– All binary one’s in the host portion


• Class B– Medium organizations– 128-191– Default SM= 255.255.0.0

• Two octets for network, 2 octets for hosts

– How many hosts available?• 216= over 65,000

– 130.52.33.7– N.N.H.H– 255.255.0.0– 185.111.99.87

Class B Example

• 167.101.52.36 255.255.0.0

• 167= Class B• Default SM for Class B= 255.255.0.0• Network portion of address= 167.101• Host portion= .52.36• Network ID= 167.101.0.0




• Class C– Small organizations– 192-223– Default SM= 255.255.255.0

• Three octets for network, 1 octet for hosts

– How many hosts available?• 28= 256-2 (254 useable)

– 199.52.33.7– N.N.N.H– 255.255.255.0– 220.111.99.87

Class C Example

• 210.44.200.89 255.255.255.0

• 210= Class C• Default SM for Class C= 255.255.255.0• Network portion of address= 210.44.200• Host portion= .89• Network ID= 210.44.200.0



Other IP Classes & More

• Class D & E not for commercial use– D is multicast (one to a group)– 224.0.0.0- 239.255.255.255

• All 0’s in host portion(s) = network ID• All 1’s in host portion(s)= broadcast• CAN NOT USE THOSE FOR HOSTS!

• Activity on 5.2.1

Handouts

• Lots of Practice!

Public/Private IP’s

• Some addresses are reserved & can not be routed across Internet

• You can have a public IP for network/servers & private for hosts inside– Saves IP addresses

Address Class

Address Range

A 10.0.0.0- 10.255.255.255

B 172.16.0.0- 172.31.255.255

C 192.168.0.0- 192.168.255.255

Private IP’s

• If host does not connect DIRECTLY to Internet, it can have a private IP

• Router BLOCKS private IP’s

• Security!!!– Private IP’s can not be seen from Internet

• 127.0.0.0 range is reserved for loopback testing

Private Nets- 5.2.2 Activity

Unicast Communication

• One-to-one or Source to destination

Broadcast Communication

• One-to-all or Source to all in segment

• All hosts will look at it

• All 1’s in host portion(s) of address

• Broadcast IP & MAC

• Default Broadcasts– A- 10.255.255.255 255.0.0.0– B- 172.16.255.255 255.255.0.0– C- 192.168.1.255 255.255.255.0

Broadcast Communication

Multicast Communication

• One-to-group

• Class D 224.0.0.0- 239.255.255.255

• Multicast MAC begins with 01-00-5E

• Where is it used?– Gaming– Distance learning

Multicast Communication

Which one?

• Unicast

• Multicast

• Broadcast

Activity & Handout

• 5.2.3.4

• Handout

• DOS– Netstat –e– Do this every 10 seconds– Pay attention to non-unicast packets

Review

1. 160.50.23.6 255.255.0.0; What network is this on?– 160.50.0.0

2. Which default SM has the most hosts?– Class A 255.0.0.0– Over 16 million!

3. How many useable hosts in a Class C?– 254

4. 220.101.5.90 255.255.255.0; What network is this on?– 220.101.5.0

Review

1. What are the private IP addresses?– 10, 172.16-172.31, 192.168.

2. What is the MAC broadcast frame in hex?– FF-FF-FF-FF-FF-FF

3. What is the MAC for a multicast?– 01-00-5E

4. One to one communication is…– Unicast

5. To send a unicast message, which addresses do you need?– Source & dest. IP & MAC

Assigning IP Addresses

• Static– Manually type in IP

Address– Good for printers

or servers• Devices people

access all the time• You wouldn’t want

their address changing!

– Good documentation!!!!


• Dynamic– Assigned auto by

DHCP server– Assigns IP, SM,

DG, more– Good for larger

networks or with mobile/new devices

– Leased addresses


• Admins have a pool of IP addresses– DHCP assigns from the pool

• SOHO routers usually have DHCP

• Medical field-– Legal requirement– Must track who is on machine– DHCP server assigns & keeps log of users

DHCP Servers• How you get on the net in a hotel, Starbucks, or BK• Either dedicated server or mixed in another device

– From ISP or on your ISR

How DHCP Works

Configuring DHCP on Linksys

• 192.168.1.1

• Packet

Tracer Lab

5.3.3.3

Review

1. Which addresses does a host use to discover a DHCP server?

– 255.255.255.255– FF-FF-FF-FF-FF-FF

2. Who sees that? Who responds?– All on the segment– The DHCP server

3. What happens to a PC’s IP when you shut down?

– Goes back to the DHCP pool of addresses

Network Boundaries

The Network In & Out

How to Connect to the ISP

• Directly– 1 PC to a modem– PC gets address from ISP

• ISR– Modem to ISR– Internal PC’s get addresses from ISR

• Gateway Device– ISR & Modem in one– Internal gets private IP’s

NAT

• Translates private into public addresses

• Prevents external from seeing internal

• A private (local) source IP address is translated to a public (global) address. – The process is reversed for incoming packets.– The integrated router is able to translate many

internal IP addresses to the same public address, by using NAT.

NAT Example

Packet Tracer

• 5.4.3.2

Review

1. Which address does the PC

need to access the Internet?– Default gateway address of the ISR

2. Which devices translates NAT?– ISR

Review

Network AddressingNetworking for Home & Small Business

network addressing

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