Learn About IP Address Classes For The CCENT Exam

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Assigning IP Address to a class is called classful addressing.

ARIN – American Registry for Internet Numbers manages the allocation of addresses.

There are five different types of classes:

Class A:

  • Created to allow very large networks
  • The first octet is used to define the network
  • The first bit has to be: 0
  • Range: 1 – 126 (actually 0 – 127, but 0 and 127 are reserved for other purposes)

Class B:

  • Created for medium sized networks
  • Uses the first two octets to define the network
  • The first two bits have to be: 10
  • Range: 128 – 191

Class C:

  • Created for many small networks
  • Uses the first three octets to define the network
  • The first three bits have to be: 110
  • Range: 192 – 223

Class D:

  • Created for multicasting
  • The first four bits have to be: 1110
  • Range: 224 – 239

Class E:

  • Reserved for the Internet Engineering task force (IETF)
  • First four bits have to be 1111
  • None of these addresses have been released for use on the internet
  • Range: 240 – 255

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