CompTIA A+ 220-901

Answer: A - The default subnet mask for the IP address 192.168.10.10 is 255.255.255.0.

Key Takeaway: The method to find out the subnet mask for a given IP address is:

1. Check the class of the IP address given (e.g. A ).
2. Determine the position in the alphabet of the class designation. A is the first letter of the alphabet, so for a class A IP address, you should come up with a value of 1. For a class B IP address, 2.
3. The number of 255s in the subnet mask is the number you determined above. For example, class A will have one 255, class B will have two 255s, and class C will have three 255s.