Subnetting Tables
by Tuirgin on Feb.09, 2010, under Networking, Technology
Hello, World. Apologies to my chess and go friends, but I have disappeared inside a dozen herniatastic tomes of dubitable verbosity in the attempt to pursue certification as a CCNA. I shall come up for air from time to time… I hope.
What follows are subnetting tables, largely based on the chapter on subnetting from Todd Lammle’s CCNA: Cisco Certified Network Associate Study Guide.
Sorry, but there’s no sex, pop-culture references, or fart jokes to be found here. Move along. There’s nothing to see here. Unless you’re trying to memorize a bunch of subnetting info. Seriously. That’s not flatulence. That’s the sound of my brain on subnetting.
Formulas
- CIDR:
Total address size – unmasked bits; i.e. 32 – unmasked bits - Unmasked bits:
32 – CIDR - Masked bits:
8 – unmasked bits - Number of subnets:
2x, where x is the number of masked bits - Hosts per subnet:
2y– 2, where y is the number of unmasked bits - Block size:
256 – subnet mask
Subnet Mask 128
| Subnet Mask | 128 |
|---|---|
| Binary | 10000000 |
| CIDR | 25 |
| Unmasked Bits | 7 |
| Masked Bits | 1 |
| Block Size | 128 |
| Subnets | 2 |
| Hosts per subnet | 126 |
Subnet Mask 192
| Subnet Mask | 192 |
|---|---|
| Binary | 11000000 |
| CIDR | 26 |
| Unmasked Bits | 6 |
| Masked Bits | 2 |
| Block Size | 64 |
| Subnets | 4 |
| Hosts per subnet | 62 |
Subnet Mask 224
| Subnet Mask | 224 |
|---|---|
| Binary | 11100000 |
| CIDR | 27 |
| Unmasked Bits | 5 |
| Masked Bits | 3 |
| Block Size | 32 |
| Subnets | 8 |
| Hosts per subnet | 30 |
Subnet Mask 240
| Subnet Mask | 240 |
|---|---|
| Binary | 11110000 |
| CIDR | 28 |
| Unmasked Bits | 4 |
| Masked Bits | 4 |
| Block Size | 16 |
| Subnets | 16 |
| Hosts per subnet | 14 |
Subnet Mask 248
| Subnet Mask | 248 |
|---|---|
| Binary | 11111000 |
| CIDR | 29 |
| Unmasked Bits | 3 |
| Masked Bits | 5 |
| Block Size | 8 |
| Subnets | 32 |
| Hosts per subnet | 6 |
Subnet Mask 252
| Subnet Mask | 252 |
|---|---|
| Binary | 11110000 |
| CIDR | 30 |
| Unmasked Bits | 2 |
| Masked Bits | 6 |
| Block Size | 4 |
| Subnets | 64 |
| Hosts per subnet | 2 |
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About Tuirgin
Tuirgin is Christopher D. Walborn. Tuirgin has a gaggle of kids and a wife that loves him despite himself. Tuirgin is part of the >14% unemployed in Lee County, FL, but is studying for the CCNA exam in hopes of improved career longevity. Benefactors wishing to enable Tuirgin's dream of being a full-time dilettante should contact him immediately. Tuirgin does not usually refer to himself in the 3rd person. Go figure.- email: christopher@tuirgin.com
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Chess Servers
February 9th, 2010 on 7:20 am
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