CIDR & Subnetting Cheat Sheet - Practice Flashcards

Twenty Q&A flashcards focusing on CIDR basics, common subnet masks, block sizes, and a practical /26 example.

What does CIDR stand for?

Classless Inter-Domain Routing

In CIDR notation, what does /24 indicate about network and host bits?

24 network bits with the remaining bits used for hosts

How many total IP addresses are in a /30 subnet?

4 total IPs

How many usable host IPs are available in a /30 subnet?

2 usable hosts

What is the subnet mask for a /29 subnet?

255.255.255.248

How many total IP addresses are in a /29 subnet?

8 total IPs

What is the subnet mask for a /28 subnet?

255.255.255.240

How many usable hosts are in a /28 subnet?

14 usable hosts

What is the subnet mask for a /27 subnet?

255.255.255.224

How many total IP addresses are in a /27 subnet?

32 total IPs

How many usable hosts are in a /27 subnet?

30 usable hosts

What is the subnet mask for a /26 subnet?

255.255.255.192

How many total IP addresses are in a /26 subnet?

64 total IPs

How many usable hosts are in a /26 subnet?

62 usable hosts

What is the subnet mask for a /25 subnet?

255.255.255.128

How many total IP addresses are in a /25 subnet?

128 total IPs

How many usable hosts are in a /25 subnet?

126 usable hosts

For the CIDR 192.168.1.130/26, what is the network ID?

192.168.1.128

For the CIDR 192.168.1.130/26, what is the broadcast address?

192.168.1.191

In the 192.168.1.130/26 subnet, what are the usable IPs?

192.168.1.129 to 192.168.1.190