How To Use Subnet Class Tool
- Input valid IP address in dotted-decimal format. Invalid input will show no results.
- The class of the subnet will determined automatically.
- Subnet class tool will not only show subnet classes ranging from A-E, but also special cases - "This" host, "This" network, loopback and broadcast.
- This tool will show address range for each class.
- Bit-wise representation of the IP address and class combination will also be shown. You can easily check bit usage for each class. Letter "n" stands for network bits, "h" for host bits and "x" is open type bit.
Classful network description
Classful network is a network addressing method replaced by CIDR addressing in 1993. Classful addressing was introduced in 1981 and is described in RFC 791. Network prefix is determined from IP address and its class. Obsolete IP version used 5 network classes:
|Class||First bits||Class address range||Subnet mask||Routing prefix||Use|
|Class A||0||0 - 18.104.22.168||255.0.0.0||/8||General|
|Class B||10||128 - 22.214.171.124||255.255.0.0||/16||General|
|Class C||110||192 - 126.96.36.199||255.255.255.0||/24||General|
|Class D||1110||224 - 188.8.131.52||Multicast|
|Class E||1111||240 - 255.255.255.254||Reserved/Experimental|
Nowadays classful network concepts can be used in private networks. With help of network address translator (NAT), private IP addresses can be translated to public addresses and vise versa. Table of private IP address ranges:
|Block||Range||Host ID size||Number of Hosts|
|24-bit||10.0.0.0 - 10.255.255.255||24||16,777,216|
|20-bit||172.16.0.0 - 172.31.255.255||20||1,048,576|
|16-bit||192.168.0.0 - 192.168.255.255||16||65,536|