What is an IP address

Finding a route to the destination is one of the main tasks of the Internet. That is one reason that the IP address must be unique in the LAN (Local Area Network), and also in the WAN (Wide Area Network).

IP does not work with fixed network connections, This means that every packet that is sent is determined its own route to arrive at its final destination. The package each time only checks the route to the next computer, just as long as you reach the destination.

Whether the package actually arrives, plays no role IP. The protocol delivers the package to fit the unique IP address where the adress resolution protocol (arp) takes over.

The ARP is a protocol within the TCP / IP that allows to establish a connection to a LAN without the MAC address (medium acces control) to know the computers. The arp accompanied the parcel , which is delivered to the unique IP address, the correct host.

To do this, it sends an ARP packet to all active hosts within the local area network. This did not happen on the basis of IP addresses, but based on MAC addresses. Each network possesses such a unique MAC address.


3.1 IPV4


An IPV4 address consists of 32 bits and is assigned to a NIC (Network Interface Card), NIC in a network is also called a host or node named. NICs are eg. In computers, printers, routers, NAS (Network-attached storage). Elke bit can 2 assume values: a 0 or a 1. There are so 232 and a number of 4.294.967.296 different addresses.

An IP Address that is not to read displays with ones and zeros and not remember. Therefore 32bits be divided into 4 octetten, 1 octet consists of 8 bits (nibble=4 bits) a can dus 28 (=256) assume binary values. The octets are separated by points, whose numbers a value between 0 in 255 can have.


Example: with reference to a drawing,.



How do I obtain this binary, a computer calculates a two-part system so only knows the numbers 0 in 1.

27=128 26=64 25=32 24=16 23=8 22=4 21=2 20=1
128 64 32 16 8 4 2 1
1 0 1 1 1 0 0 1



conversion binary to decimal is easy because you are the true bits but have to count on,

11000000 = 128+64 = 192

10100000 = 128=32 = 168

00001010 = 8+2 = 10

00010001 = 16=1 = 17

Representing an IPV4 address

conversion decimal to binary is slightly harder,, we start with 192.

We share 192 getting through 2, it is divisible by 2 the residual value is o, it is not divisible by 2 the residual value 1.

192:2 = 96 residual value 0

096:2 = 48 residual value 0

048:2 = 24 residual value 0

024:2 = 12 residual value 0

012:2 = 06 residual value 0

006:2 = 03 residual value 0

003:2 = 1,5 is residual value 1 (if the number is not divisible by 2 get this residual value 1, everything gets deleted after the comma and further divided)

001:2 = 0,75 residual value 1

If we read from below upwards we can see our binary digit, namely: 11000000.

This is done so at 168,10 in 17 so you finally have a binary outcome 11000000.10100000.00001010.00010001

3.2 network Classes

Hosts share the same network can communicate directly with each other, hosts with a different network share can not do this. These will need to use one or more intermediate routers to achieve their goal.

Networks are divided into classes , each network is of a particular class. To which class belongs to a network, you see the value of the first octet. Depending on the classes 1,2 of 3 octets used for netwerkindentificatie.


IP addresses are 3 split classes:

  • class A
  • class B
  • class C


3.2.1 A Class A network

The value of the octet is between 1 in 126, because the first byte is the network ID, are there 126 A network-welding to distribute. This value is fixed so that the other 3 octets yet 16.777.214 addresses is available.


3.2.2 A class B network

In a class B network, the values ​​are fixed in the first 2 octetten, The B-Class uses the values ​​of the first octet in the range 128 t.e.m. 192. What an available number of 65.534 has. Class B networks are designed for small to medium enterprises.


3.2.3 A class C network

In a class C network, the values ​​of the first 3 octetten vast, the value of the first octet is in the range of 192 t.e.m. 223.

The class C network uses the values 192.0.1 t.e.m. 223.255.254 the network address of the first 3 octetten.

For the last octet, there are still 254 IP-addressn over.

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