IP Address

Classful Addressing

Class

Address Range

Subnet masking

Example IP

Leading bits

Max number of networks

Application

IP Class A

1 to 126

255.0.0.0

1.1.1.1

8

128

Used for large number of hosts.

IP Class B

128 to 191

255.255.0.0

128.1.1.1

16

16384

Used for medium size network.

IP Class C

192 to 223

255.255.255.0

192.1.11.

24

2097157

Used for local area network.

IP Class D

224 to 239

NA

NA

NA

NA

Reserve for multi-tasking.

IP Class E

240 to 254

NA

NA

NA

NA

This class is reserved for research and Development Purposes.

  • All bits of network ID set to 1 are reserved for use as an IP broadcast address and cannot be used.

  • All bits of network ID are set to 0. They are used to denote a particular host on the local network and should not be routed.

Key differences between public and private IP addresses

The main difference between public and private IP addresses is how far they reach, and what they’re connected to. A public IP address identifies you to the wider internet so that all the information you’re searching for can find you. A private IP address is used within a private network to connect securely to other devices within that same network.

Your private IP address exists within specific private IP address ranges reserved by the Internet Assigned Numbers Authority (IANA) and should never appear on the internet.

  • Class A: 10.0.0.0 — 10.255.255.255

  • Class B: 172.16.0.0 — 172.31.255.255

  • Class C: 192.168.0.0 — 192.168.255.255

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