A network diagnostic can define as a procedure used to determine computer's network configuration and troubleshoot Internet problems. So we can say that network diagnostic usually will help locate the cause of the connection problems. These procedures are usually performed using hardware or software network diagnostic tools. So these Network Diagnostics utilities can use to perform a scan of the system and test network connectivity and whether or not network related programs and services are functional and it would be helpful to determine the diagnose whether there is a problem and what it is.
There are number of advantages of network diagnostic tools as follows,
Check for network adapter issue and validate IP configuration
Gather a variety of information which can be helpful for troubleshooting.
Check DNS and gateway settings and functionality
Perform a scan of the system and test network connectivity and whether or not to the network related programs and services are functional.