A network administrator wants to narrow the scope of a subnet to two usable IP addresses within a class C network.
Which of the following is the correct CIDR notation?
A.
10.10.50.0/30 B.
172.16.20.0/30 C.
192.1.0.124/30 D.
192.168.0.192/24 E.
192.170.10.0/24
C.
A network administrator wants to narrow the scope of a subnet to two usable IP addresses within a class C network.
Which of the following is the correct CIDR notation?
A.
10.10.50.0/30
B.
172.16.20.0/30
C.
192.1.0.124/30
D.
192.168.0.192/24
E.
192.170.10.0/24
C.
The correct CIDR notation to narrow the scope of a subnet to two usable IP addresses within a class C network is /30.
CIDR notation is a way of representing an IP address and its associated network mask in a compact form. The network mask indicates which bits of the IP address represent the network portion of the address and which bits represent the host portion.
In a class C network, the default network mask is 255.255.255.0, which means that the first three octets (24 bits) represent the network portion of the address, and the last octet (8 bits) represents the host portion. To create a subnet with only two usable IP addresses, we need to borrow two bits from the host portion of the address and use them to create subnets. This results in a network mask of 255.255.255.252 (or /30 in CIDR notation), which leaves only two bits for host addresses.
Option A: 10.10.50.0/30 - This is a valid CIDR notation for a subnet with only two usable IP addresses within a class A network. However, the question specifically asks for a class C network, so this option is incorrect.
Option B: 172.16.20.0/30 - This is a valid CIDR notation for a subnet with only two usable IP addresses within a class B network. However, the question specifically asks for a class C network, so this option is incorrect.
Option C: 192.1.0.124/30 - This is a valid CIDR notation for a subnet with only two usable IP addresses within a class C network. It uses a network mask of 255.255.255.252, which leaves only two bits for host addresses.
Option D: 192.168.0.192/24 - This is a valid CIDR notation for a subnet with 256 usable IP addresses within a class C network. It uses the default network mask of 255.255.255.0.
Option E: 192.170.10.0/24 - This is a valid CIDR notation for a subnet with 256 usable IP addresses within a class C network. It uses the default network mask of 255.255.255.0.
Therefore, the correct CIDR notation to narrow the scope of a subnet to two usable IP addresses within a class C network is C. 192.1.0.124/30.