IP Address Versi 4

Explanation
The correct answer is 172.28.0.0/16 and 172.30.0.0/16. These two IP address blocks fall within the range of private IP addresses for class B networks. The first octet of the IP address in both cases is 172, which falls within the range of 172.16.0.0 to 172.31.255.255, designated for private use. Therefore, these two IP address blocks can be used for the company's intranet.

Explanation
The correct answer is 192.168.19.0/24 because it falls under the range of private IP addresses specified for Class C networks. Private IP addresses are used for internal communication within a network and are not routable on the internet. The /24 indicates that the first 24 bits of the IP address are the network address, leaving 8 bits for host addresses. This allows for a maximum of 256 host addresses in the network.

Explanation
The correct answer is 10.0.0.0/8 because a private network using IP address class A requires an IP address range that starts with 10.x.x.x. The /8 subnet mask indicates that the first 8 bits of the IP address are fixed, allowing for a range of 10.0.0.0 to 10.255.255.255, providing a large number of available IP addresses for internal use within the company.

Explanation
The correct answer is 255.255.255.0. The default subnet mask for a Class C IP address is 255.255.255.0. This subnet mask allows for a maximum of 254 hosts on the network, with the first three octets (255.255.255) representing the network portion and the last octet (0) representing the host portion.

Explanation
The subnet mask that is automatically displayed after inputting the IP address 202.67.19.5 correctly is 255.255.255.0. This subnet mask is commonly used for a Class C network, where the first three octets of the IP address represent the network portion and the last octet represents the host portion. The subnet mask 255.255.255.0 indicates that the first three octets are the network portion, allowing for 254 hosts on the network.

Explanation
The correct answer is 255.255.0.0 or /16. This is because the given IP address blocks have a common network address of 0.0.0.0 in the first two octets. A subnet mask of /16 allows for 16 bits to be used for the network portion of the IP address, leaving 16 bits for the host portion. This allows for a maximum of 65,536 possible host addresses within each IP address block.

Explanation
The network address of the host can be determined by looking at the IP address and the default gateway. In this case, the IP address of the host is 123.45.6.78 and the default gateway is 123.45.6.87. The network address is obtained by setting all the bits in the host portion of the IP address to zero. Therefore, the network address in this case is 123.45.0.0.

Explanation
The host with IP address 123.45.6.78 and default gateway 123.45.6.87 is on the same network as the PCs with IP addresses 123.45.6.1 and 123.45.0.100. This is because the first three octets (123.45.6) of the host's IP address, default gateway, and the two given PC IP addresses are the same. This indicates that they are all part of the same network. The other two PC IP addresses (123.45.67.1 and 123.45.67.100) have a different third octet, which means they are on a different network.

Explanation
The IP address of the host is 203.45.6.78 and the default gateway is 203.45.6.87. In order for two devices to be on the same network, they must have the same network address. The network address is determined by the first three octets of the IP address. Therefore, the devices with IP addresses 203.45.6.100 and 203.45.6.240 are on the same network as the host because they have the same network address (203.45.6.x). The other two devices have different network addresses and are not on the same network as the host.

Explanation
The given host has an IP address of 12.34.56.78 and a default gateway of 12.34.56.80. In order for two devices to be on the same network, their IP addresses must have the same network portion.

Looking at the answer choices, the IP addresses 12.0.0.80 and 12.3.4.5 both have the same network portion (12.x.x.x) as the given host's IP address, indicating that they are on the same network. Therefore, these two IP addresses are the correct answers.

Explanation
The given IP addresses are in the range of 100.100.100.64/26, 100.100.100.127/26, 100.100.100.223/26, and 100.100.100.190/26. A /26 subnet mask allows for 64 IP addresses, with 62 usable addresses for hosts. The IP addresses 100.100.100.223/26 and 100.100.100.190/26 fall within this range and can be used for router interfaces.