Binary to Decimal Conversion

128 64 32 16 8 4 2 1

27 26 25 24 23 22 21 20

IP AddressesIP Addresses

A computer only knows binary (0s and 1s)

An IP address in IP version 4 has 32 bits

(separated by periods into 4 octets)

11000000.10101000.00001010.10010110

IP AddressesIP Addresses Humans are more familiar with

decimal numbers, so we use a

Dotted decimal formatAn IP address of 192.168.10.150

has a Binary equivalent of 11000000.10101000.00001010.10010110

Conversion can be done in Windows calculator. Make sure to include any leading zeros to make a full octet.

IP AddressesIP AddressesIP Addresses have 2 Parts:IP Addresses have 2 Parts:

Network NumberNetwork Number and and Host NumberHost Number..

In the IP Address In the IP Address 192192..168168..1010..150150

the the Network NumberNetwork Number is is 192192..168168..1010

and the and the Host NumberHost Number is is 150150

The Correct Notation is The Correct Notation is 192192..168168..1010..00

and and 00..00..00..150150

IP AddressesIP Addresses

IP Address Classes

Class Decimal Binary

A 0-126 00000000 - 01111110

B 128-191 1000000 - 10111111

C 192-223 11000000 – 11011111

IP AddressesIP Addresses• In binary, the highest number 8 bits can

designate is 11111111 or 255 in decimal.

IP Class Subnet masks

Class Subnet mask - Decimal Subnet mask - Binary

A 255.0.0.0 11111111.00000000.00000000.00000000

B 255.255.0.0 11111111.11111111.00000000.00000000

C 255.255.255.0 11111111.11111111.11111111.00000000

IP AddressesIP AddressesTo differentiate between the network portion and the host

portion, network administrators use subnet maskssubnet masks.

The default subnet masksubnet mask for the Class C IP address of 192.168.10.150 is 255.255.255.0

In binary:

11000000.10101000.00001010.10010110

11111111.11111111.11111111.00000000

11000000.10101000.00001010.00000000

192 .168 .10 .0

Convert decimal to binary in Convert decimal to binary in Windows calculatorWindows calculator

• Go to Start, Run and type in: calc

• Type in a decimal number: 100• Click on radio button beside bin (binary)

and the binary equivalent will show in the answer box: 1100100 (7 bits)

• Be careful the answer box doesn’t show leading 0s: 01100100 (8 bits)

Ipconfig - Windows 2000Ipconfig - Windows 2000

• Go to Start, Run and type in cmd

• Type in ipconfig /?

• Type in ipconfig /all

• Type in ipconfig /release

• Type in ipconfig /renew

PINGPINGPacket Internet Groper (PING) is a utility

that can verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network.

• Type ping 127.0.0.1• Type ping your IP address• Type ping another computer in your

network• Type ping your default gateway• Type ping www.yahoo.com (internet host)

An Example• Subnet a Class C network, 200.133.175.0, into 14

subnets for security, traffic control and multiple locations.

• 2n - 2 = number of subnets (need minimum of 14 subnets) where n = number of bits borrowed2?-2 > 1424-2 = 16

• Borrow four bits = subnet mask 255.255.255.240• Table

An Example

200.133.175.0 11001000.100000101.10101111.00000000

255.255.255.240

11111111.11111111.11111111.11110000

Example