StationX

h1.site-description { display: none; }

Cyber Security Blog

IPv4 Subnet Cheat Sheet

Nathan House

by

To supplement the courses in our Cyber Security ​Career Development Platform, here is our IPv4 Subnet Cheat Sheet. 

PDF download also available.

SUBNETS

CIDR
SUBNET MASK
OF ADDRESSES
WILDCARD
/32255.255.255.25510.0.0.0
/31255.255.255.25420.0.0.1
/30255.255.255.25240.0.0.3
/29255.255.255.24880.0.0.7
/28255.255.255.240160.0.0.15
/27255.255.255.224320.0.0.31
/26255.255.255.192640.0.0.63
/25255.255.255.1281280.0.0.127
/24255.255.255.02560.0.0.255
/23255.255.254.05120.0.1.255
/22255.255.252.01,0240.0.3.255
/21255.255.248.02,0480.0.7.255
/20255.255.240.04,0960.0.15.255
/19255.255.224.08,1920.0.31.255
/18255.255.192.016,3840.0.63.255
/17255.255.128.032,7680.0.127.255
/16255.255.0.065,5360.0.255.255
/15255.254.0.0131,0720.1.255.255
/14255.252.0.0262,1440.3.255.255
/13255.248.0.0524,2880.7.255.255
/12255.240.0.01,048,5760.15.255.255
/11255.224.0.02,097,1520.31.255.255
/10255.192.0.04,194,3040.63.255.255
/9255.128.0.08,388,6080.127.255.255
/8255.0.0.016,777,2160.255.255.255
/7254.0.0.033,554,4321.255.255.255
/6252.0.0.067,108,8643.255.255.255
/5248.0.0.0134,217,7287.255.255.255
/4240.0.0.0268,435,45615.255.255.255
/3224.0.0.0536,870,91231.255.255.255
/2192.0.0.01,073,741,82463.255.255.255
/1128.0.0.02,147,483,648127.255.255.255
/00.0.0.04,294,967,296255.255.255.255

DECIMAL TO BINARY

SUBNET MASK
WILDCARD
255  1111 11110        0000 0000
254  1111 11101        0000 0001
252  1111 11003        0000 0011
248  1111 10007        0000 0111
240  1111 000015      0000 1111
224  1110 000031      0001 1111
192  1100 000063      0011 1111
128  1000 0000127    0111 1111
0       0000 0000255    1111 1111

BINARY TO DECIMAL

IP ADDRESS CLASSES

A0.0.0.0 – 127.255.255.255
B128.0.0.0 – 191.255.255.255
C192.0.0.0 – 223.255.255.255
D224.0.0.0 – 239.255.255.255
E240.0.0.0 – 255.255.255.255

RESERVED (PRIVATE) RANGES

CLASS A10.0.0.0 – 10.255.255.255
CLASS B172.16.0.0 – 172.31.255.255
CLASS C192.168.0.0 – 192.168.255.255
LOCALHOST127.0.0.0 – 127.255.255.255
ZEROCONF (APIPA/BONJOUR)169.254.0.0 – 169.254.255.255

TERMINOLOGY

WILDCARD MASKA wildcard mask indicates which parts of an IP address are available for examination.
CIDRClassless interdomain routing was developed to provide more granularity
than legacy classful addressing; CIDR notation is expressed as /XX

Nathan House is the founder and CEO of Station X a cyber security training and consultancy company. He has over 25 years experience in cyber security where he has advised some of largest companies in the world, assuring security on multi-million and multi-billion pound projects. Nathan is the author of the popular "The Complete Cyber Security Course" which has been taken by over half a million students in 195 countries. Winner of the AI "Cyber Security Educator of the Year 2020" award. Over the years he has spoken at a number of security conferences, developed free security tools, and discovered serious security vulnerabilities in leading applications. PGP Fingerprint : CBA3FBF729FB00CB21D64FB00E7955AE6E37FEF1

    • >