IP address classes

Class1st Octet Decimal Range1st Octet High Order Bits

Network/Host ID
(N=Network, H=Host)

Default Subnet MaskNumber of NetworksHosts per Network
(Usable Addresses)
A 1 – 126* 0 N.H.H.H 255.0.0.0 126 (27 – 2) 16,777,214 (224 – 2)
B 128 – 191 10 N.N.H.H 255.255.0.0 16,382 (214 – 2) 65,534 (216 – 2)
C 192 – 223 110 N.N.N.H 255.255.255.0 2,097,150 (221 – 2) 254 (28 – 2)
D 224 – 239 1110 Reserved for Multicasting
E 240 – 254 1111 Experimental; used for research

Note: Class A addresses 127.0.0.0 to 127.255.255.255 cannot be used and is reserved for loopback and diagnostic functions.

 

Private IP Addresses

ClassPrivate NetworksSubnet MaskAddress Range
A 10.0.0.0 255.0.0.0 10.0.0.0 - 10.255.255.255
B 172.16.0.0 - 172.31.0.0 255.240.0.0 172.16.0.0 - 172.31.255.255
C 192.168.0.0 255.255.0.0 192.168.0.0 - 192.168.255.255


Subnet Mask Cheat Sheet

 AddressesHostsNetmaskAmount of a Class C
/30 4 2 255.255.255.252 1/64
/29 8 6 255.255.255.248 1/32
/28 16 14 255.255.255.240 1/16
/27 32 30 255.255.255.224 1/8
/26 64 62 255.255.255.192 1/4
/25 128 126 255.255.255.128 1/2
/24 256 254 255.255.255.0 1
/23 512 510 255.255.254.0 2
/22 1024 1022 255.255.252.0 4
/21 2048 2046 255.255.248.0 8
/20 4096 4094 255.255.240.0 16
/19 8192 8190 255.255.224.0 32
/18 16384 16382 255.255.192.0 64
/17 32768 32766 255.255.128.0 128
/16 65536 65534 255.255.0.0 256


Found this article interesting?
Subscribe to DomainRegister´s newsletter!

You can unsubscribe at any time by simply clicking the link in the footer of our emails. For information about our privacy practices, please visit our website.

We use Mailchimp as our marketing platform. By clicking below to subscribe, you acknowledge that your information will be transferred to Mailchimp for processing. Learn more about Mailchimp s privacy practices here.

  • networking
  • 1 Users Found This Useful
Was this answer helpful?

Related Articles

 Global Capacity of Different RAID Levels

RAID (originally redundant array of inexpensive disks, now commonly redundant array of...

 What is a 1U unit?

Rack space is vertically divided in "rack units", conventionally referred to as "U" (sometimes...