IP Address Classes & Subnetting

IP Address Classes

Importent Note:

• Class A addresses 127.0.0.0 to 127.255.255.255 cannot be used and is reserved for loopback and diagnostic functions.
• a.b.c.1  to  a.b.c.10 – usually routers and servers
• a.b.c.11  to  a.b.c.204 – usually workstations
• a.b.c.241  to  a.b.c.254 – usually UNIX (or Linux) hosts
• 10.0.0.0  to 10.255.255.255 – usually Internal networks
• 172.16.0.0  to  172.31.255.255 – usually Intranets not connected to the Internet
• 192.168.0.0  to 192.168.255.255 – usually networks connected to the Internet
  (and usually behind a firewall)

IP Subnet Table