Question 1

What is CIDR notation?

Accepted Answer

Classless Inter-Domain Routing uses a slash and prefix length (e.g., /24) to denote how many bits are network vs host.

Question 2

How many hosts are in a subnet?

Accepted Answer

For IPv4 /n, usable hosts are 2^(32-n) - 2 (excluding network and broadcast) in traditional schemes.

Question 3

What is the network and broadcast address?

Accepted Answer

The network address has all host bits 0; the broadcast has all host bits 1 for IPv4.

Question 4

Do IPv6 subnets have broadcast addresses?

Accepted Answer

No—IPv6 does not use broadcast; it uses multicast.

Question 5

How do I find the next subnet?

Accepted Answer

Increment the network address by the block size: block = 2^(host bits).

Subnet Calculator