When configuring single-area OSPF, what wildcard mask would be used for the network 172.20.0.0 255.255.252.0?

When configuring OSPF with a specific network, the wildcard mask is used to determine which bits of the IP address will be matched by the OSPF configuration. In this case, the IP address is 172.20.0.0 and the subnet mask is 255.255.252.0.

To convert the subnet mask to a wildcard mask, you need to subtract each octet of the subnet mask from 255. The subnet mask 255.255.252.0 can be broken down as follows:

• The first octet: 255 - 255 = 0

• The second octet: 255 - 255 = 0

• The third octet: 255 - 252 = 3

• The fourth octet: 255 - 0 = 255

Combining these results gives you the wildcard mask 0.0.3.255.

This wildcard mask indicates that the first two octets (172.20) are fixed and must match exactly, while the last two octets can vary based on the OSPF configuration. The "3" in the third octet corresponds to the binary representation where the subnet allows for a range of addresses, specifically the