let’s subnet your home network // You SUCK at subnetting // EP 6

About this video

Episode 6 of the ‘You Suck at Subnetting’ series applies subnetting to a practical task: splitting a single home network into four smaller networks for wireless, IoT, DMZ and users, for better separation and security. The method starts by reading the subnet mask in binary, where 1 bits are network bits and 0 bits are host bits. To get more networks you must borrow host bits and convert them into network bits. Using a powers-of-two chart, four networks require borrowing two bits (if you needed 17 networks, you would need five bits to reach 32). Flipping those two bits in the last octet changes the mask to 255.255.255.192, or /26 in CIDR notation. The increment — the value of the last network bit — is 64, so the new networks step in blocks of 64, starting with 192.168.1.0 through .63 and then .64 through .127, and so on. With six host bits remaining, each network has 2 to the power of 6 equals 64 addresses, minus the network and broadcast addresses, leaving 62 usable hosts. He assigns homework to repeat the process for five networks and notes the same steps work for Class A and B addresses too.

Key takeaways

• Subnetting creates more networks by borrowing host bits (the 0s in the mask) and turning them into network bits (1s)
• Number of bits to borrow comes from a powers-of-two chart: 4 networks need 2 bits; round up, e.g. 17 networks need 5 bits for 32
• Borrowing 2 bits from a /24 gives a 255.255.255.192 mask, written as /26
• The increment is the value of the last network bit — 64 here — so network ranges step by 64 addresses
• Usable hosts per subnet are 2^(remaining host bits) minus 2: with 6 host bits, 64 total and 62 usable addresses

Episode details: published September 9, 2022 · 9:40 long. Summary written by Self Growth Videos from the episode itself. Business results and any income figures mentioned are NetworkChuck’s own claims, shared for education — they are not typical or guaranteed.

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