Following is a list of all Class B and C subnet masks and their maximum hosts and subnets. The last two octets (16 bits) of Class B and the last octet (8 bits) of Class C addresses are divided between hosts and subnets. At the end, all Class C masks are shown in more detail.
Class C Subnet Masks
The last 8 bits of the mask are divided between subnets and hosts. Using a Class C address, a network administrator has to determine how best to split up the network: more subnets and fewer hosts or more hosts and fewer subnets.
Class A, B & C Subnet Masks
This is an overview of subnet masks used in all three major network classes. The IP address is first divided between networks and hosts. The host bits are further divided between subnets and hosts.
CLASS B SUBNET MASKS
How 16
Bits Are Maximum Maximum
Subnet Mask Divided Subnets Hosts
255.255.192.0 2/14 2 16,382
255.255.224.0 3/13 6 8,190
255.255.240.0 4/12 14 4,094
255.255.248.0 5/11 30 2,046
255.255.252.0 6/10 62 1,022
255.255.254.0 7/9 126 510
255.255.255.0 8/8 254 254
255.255.255.128 9/7 510 126
255.255.255.192 10/6 1,022 62
255.255.255.224 11/5 2,046 30
255.255.255.240 12/4 4,094 14
255.255.255.248 13/3 8,190 6
255.255.255.252 14/2 16,382 2
CLASS C SUBNET MASKS
How 8
Bits Are Maximum Maximum
Subnet Mask Divided Subnets Hosts
255.255.255.192 2/6 2 62
255.255.224.224 3/5 6 30
255.255.240.240 4/4 14 14
255.255.248.248 5/3 30 6
255.255.252.252 6/2 62 2
Class C Subnet Masks
The last 8 bits of the mask are divided between subnets and hosts. Using a Class C address, a network administrator has to determine how best to split up the network: more subnets and fewer hosts or more hosts and fewer subnets.
Class A, B & C Subnet Masks
This is an overview of subnet masks used in all three major network classes. The IP address is first divided between networks and hosts. The host bits are further divided between subnets and hosts.
 | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2008 The Computer Language Company Inc. All rights reserved. |
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