IPv4 IP Address Classes, Ranges, & Subnet Masks

 IPv4 Addresses

• Class D is for multicasting
• Class E is experimental

 

Default subnet masks

• Class A: 255.0.0.0 (/8)
• Class B: 255.255.0.0 (/16)
• Class C: 255.255.255.0 (/24)

 

RFC1918 Private IP Address Ranges

• 10.0.0.0 to 10.255.255.255 (Class A)
• 172.16.0.0 to 172.31.255.255 (Class B)
• 192.168.0.0 to 192.168.255.255 (Class C)

 

APIPA (Automatic Private IP Addressing)

169.254.0.0 to 169.254.255.255

 

Loopback

127.0.0.1 to 127.255.255.255