IP Tutorial 1

2 An IP address is a unique number used to identify your computer on the internet. Every system has it’s own unique IP address. IP addresses are layer 3, logical addresses. An IP address is a unique number used to identify your computer on the internet. Every system has it’s own unique IP address. IP addresses are layer 3, logical addresses. IP Address

IP Tutorial3 IP Structure An IP address is made up of 32 bits. Each byte is represented by a decimal and number separated by a full stop (period):

IP Tutorial4 IP Structure Is an IP address, each value can never be more than 255: Is an invalid IP address, the maximum for each byte is 255 (FF hexadecimal).

IP Tutorial5 IP addresses are essential, they are used to give your computer a unique identity. Without IP addresses routing would be impossible. Say you send out a ping to a computer on a different network, your packets are sent to the router (gateway) on your network. The router checks the IP address in the packet headers, if the router knows the network on which that IP is located, it forwards it on, if it doesn’t, it forwards it on to another router that might know where the IP address is. This continues until the packet arrives at a router that can forward it onto the destination IP’s network, where it can then be picked up. Without IP addresses this wouldn’t work.

IP Tutorial6 IP addresses are separated into classes, let’s have a look at how they’re separated, then i’ll explain why: IP addresses are separated into classes, let’s have a look at how they’re separated, then i’ll explain why: Range Class 0-127A B C IP Address Classes

IP Tutorial7 Now to find out which class an IP address is in, you look at the first byte of the address: The first byte is 213. This falls inside the class range making this a class C IP address The first byte is 24. This falls inside the class range making this a class A IP address. IP Address Classes

IP Tutorial8 When I first read about IP addresses being split up into classes, the author failed to explain why it was done, so i assumed this wasn’t very important, that someone just put them into classes on a Sunday while they were bored or something. Take a look at the table below: RangeClassN/H 0-127AN.H.H.H BN.N.H.H CN.N.N.H Why?

IP Tutorial9 N = Network I.D and N = Network I.D and H = Host I.D. In a class A IP address the first byte is part of the network I.D. The remaining three bytes are part of the host I.D. This means in class A there can be fewer networks and many hosts. 1. There can be 255 networks. 2. There can be 255 x 255 x 255 = 16,581,375 theoretical hosts on each class A network.

IP Tutorial10 In class B the first two bytes are part of the network I.D and the remaining two are part of the host I.D. This means in class B there can be a reasonable amount of networks, and a reasonable amount of hosts on each one of those networks. In class B the first two bytes are part of the network I.D and the remaining two are part of the host I.D. This means in class B there can be a reasonable amount of networks, and a reasonable amount of hosts on each one of those networks x 255 = 65,025 networks x 255 = 65,025 theoretical hosts on each of those networks.

IP Tutorial11 I’m sure you get the drift, class C: 255 x 255 x 255 = 16,581,375 networks. 255 x 255 x 255 = 16,581,375 networks. 255 theoretical hosts on each of those networks. 255 theoretical hosts on each of those networks.

IP Tutorial12 I say “theoretical” hosts on each class of network, because on each network the first address and the last address cannot be used. So if you work out the theoretical number of hosts then take away two you have the actual number of host computers that can be on that same network.. I say “theoretical” hosts on each class of network, because on each network the first address and the last address cannot be used. So if you work out the theoretical number of hosts then take away two you have the actual number of host computers that can be on that same network.. Why Theoretical?

IP Tutorial13 IP Address: This is a class C address is the NETWORK address. This cannot be used as a hosts IP address is the BROADCAST address on this network. It cannot be used as a hosts IP address. Class C networks have a theoretical 255 hosts on each network, 255 – 2 = 253. So on each class C network you can have 253 host computers.

IP Tutorial14 Let’s go over a couple of examples to make this stick. What is the IP Class, Network ID, Network Broadcast Address and the Number of Hosts on the Network of the following IP Addresses Let’s go over a couple of examples to make this stick. What is the IP Class, Network ID, Network Broadcast Address and the Number of Hosts on the Network of the following IP Addresses IP: IP:

IP Tutorial15 Is a class C address, N.N.N.H The network ID is The network broadcast address is There can be 255 Theoretical hosts on this network. Thus there can be 255 – 2 = 253 host computers functioning on this network. IP:

IP Tutorial16 Is a class A address, N.H.H.H The network ID is 24.0 The network broadcast address is There can be 255×255 x 255 = 16,581,375 Theoretical hosts on this network. Thus there can be 16,581,375 – 2 = 16,581,373 host computers functioning on this network. IP:

IP Tutorial17 Try applying the above to your IP address, what class network are you on? What’s the network I.D? What’s the broadcast address? How many hosts can be on your network? Try applying the above to your IP address, what class network are you on? What’s the network I.D? What’s the broadcast address? How many hosts can be on your network?