IPv4 Address Classes Based on First-Octet Values

IPv4 Address Classes Based on First-Octet Values

1. 0

   • Class A
     • Reserved

2. 1-126

   • Class A
     • Unicast addresses, class A network

3. 127

   • Class A
     • Reserved

4. 128-191

   • Class B
     • Unicast addresses, class B networks

5. 192-223

   • Class C
     • Unicast addresses, class C networks

6. 224-239

   • Class D
     • Multicast addresses, not used as unicast IP addresses

7. 240-255

   • Class E
     • Experimental. Not used as unicast IP addressses