What subnet mask would the 10.0.0.0/24 network use?
A. 255.0.0.0
B. 255.255.0.0
C. 255.255.255.0
D. 0.0.0.255
The correct answer and explanation is:
The correct answer is C. 255.255.255.0.
Explanation:
The notation 10.0.0.0/24 represents an IP network using CIDR (Classless Inter-Domain Routing) notation. The number after the slash (“/24”) indicates the number of bits used for the network portion of the IP address. In this case, “/24” means that the first 24 bits of the IP address are reserved for the network portion, and the remaining 8 bits are used for host addresses.
To understand how this translates to a subnet mask, let’s break it down:
- CIDR Notation: The “/24” means 24 bits of the IP address are for the network. In binary, the subnet mask for a /24 network would look like this:
11111111.11111111.11111111.00000000Each group of 8 bits corresponds to one octet in the subnet mask. The “1” bits represent the network part of the address, and the “0” bits represent the host part. - Subnet Mask in Decimal: When converting the binary form to decimal, each octet of the subnet mask is converted individually:
- 11111111 (binary) = 255 (decimal)
- 11111111 (binary) = 255 (decimal)
- 11111111 (binary) = 255 (decimal)
- 00000000 (binary) = 0 (decimal)
- Why not other options?:
- A. 255.0.0.0 would be a /8 network, meaning the first 8 bits are for the network, not 24.
- B. 255.255.0.0 would be a /16 network, meaning the first 16 bits are for the network, not 24.
- D. 0.0.0.255 is not a valid subnet mask.
Thus, the correct subnet mask for the 10.0.0.0/24 network is 255.255.255.0. This allows for 256 IP addresses in total (including the network and broadcast addresses), with 254 usable host addresses.