Subnet

From MattWiki
  • Class A addresses have their first octet in the range 1 to 126 (binary address begins with 0).
  • Class B addresses have their first octet in the range 128 to 191 (binary address begins with 10).
  • Class C addresses have their first octet in the range 192 to 223 (binary address begins with 110).
CIDR Subnet Mask Number of Subnets Number of Hosts per Subnet
Class A Network
/8 255.0.0.0 1 16777214
/9 255.128.0.0 2 8388606
/10 255.192.0.0 4 4194302
/11 255.224.0.0 8 2097150
/12 255.240.0.0 16 1048574
/13 255.248.0.0 32 524286
/14 255.252.0.0 64 262142
/15 255.254.0.0 128 131070
Class B Network
/16 255.255.0.0 1 65534
/17 255.255.128.0 2 32766
/18 255.255.192.0 4 16382
/19 255.255.224.0 8 8190
/20 255.255.240.0 16 4094
/21 255.255.248.0 32 2046
/22 255.255.252.0 64 1022
/23 255.255.254.0 128 510
Class C Network
/24 255.255.255.0 1 254
/25 255.255.255.128 2 126
/26 255.255.255.192 4 62
/27 255.255.255.224 8 30
/28 255.255.255.240 16 14
/29 255.255.255.248 32 6
/30 255.255.255.252 64 2
/32 255.255.255.255 255 1 - Loopback

http://www.subnet-calculator.com/subnet.php