Subnet Mask

© 2019 Eric Skagerberg (All rights reserved. This material may not be reproduced in printed or electronic format without the express permission of the author.)
Adjunct Instructor, Computer Studies Department
Santa Rosa Junior College, California

Page last updated 8 May, 2019

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Shown in dotted decimal
- But in binary, it's a row of 1's (network) followed by a row of 0's (host).

For example, 255.255.255.0:
```
11111111.11111111.11111111.00000000
```
... splits our address 192.168.1.12:
```
11000000.10101000.00000001.00001100
```
... into network 192.168.1.0:
```
11000000.10101000.00000001.00000000
```
... and host (individual computer) 12:
```
00000000.00000000.00000000.00001100
```