It’s not that kind of CIDR



Which of these subnet masks is represented by the CIDR notation of /16?

A) 255.255.255.0

B) 16.0.0.0

C) 255.0.0.0

D) 165.245.0.0

E) 255.255.0.0

F) I’d like another glass of that


The answer: E) 255.255.0.0

The /16 CIDR notation refers to a 16 bit subnet mask, which would be the binary equivalent of 11111111.11111111.0000000.00000000, or 16 ones. If you convert this value to decimal, you would have a mask of 255.255.0.0.

Want to know more? Watch “TCP/IP Subnets.”

Our TCP/IP networks are separated into many subnets. In this video, you’ll learn about the fundamentals of IP subnetting and how legacy class-based and modern classless subnetting is used to connect the worldwide Internet.