Subnet Mask to Dotted Decimal Notation

To convert a binary subnet mask to dotted decimal notation, follow these steps:

1. Divide the subnet mask into octets by writing the 32-bit binary subnet mask with periods inserted at the octet boundaries:

   11111111.11111111.11110000.00000000
   

2. For every all-ones octet, write down 255. For every all-zeros octet, write down 0.

3. Convert the mixed octet to decimal using the binary conversion techniques add up the bit position values for all one bits
   

4. Write down the final dotted decimal address:

   255.255.240.0