Final answer:
The student's question about potential issues with a CIDR block of subnets reveals an overlap problem. The four /22 subnets provided share the same address space, which is not permitted in subnetting. A single /22 subnet covers the IP address range indicated by all the subnets listed, which demonstrates the issue of improper configuration and overlap.
Step-by-step explanation:
The student has inquired about potential issues with a group of subnets within a CIDR block. The subnets mentioned are 192.168.68.0/22, 192.168.69.0/22, 192.168.70.0/22, and 192.168.71.0/22. Upon examination, we find that these subnets do indeed have a problem. The notation /22 indicates that the first 22 bits of the IP address are reserved for the network portion, which leaves 10 bits for host addresses. A subnet with a /22 prefix has 2^10, or 1024, possible IP addresses.
When we calculate the address range for the first subnet, 192.168.68.0/22, it spans from 192.168.68.0 to 192.168.71.255, encompassing all addresses within that range. However, the subsequent subnets, such as 192.168.69.0/22, overlap with this range. This means there is an improper configuration as multiple subnets cannot occupy the same IP address space. Therefore, there should only be one /22 subnet block instead of four overlapping ones.
The correct address range for a single /22 subnet starting at 192.168.68.0 would include all subnets and IP addresses from 192.168.68.0 through 192.168.71.255.=