Final answer:
When a host name is not fully qualified, it can lead to resolution problems as the system might use a local domain to complete the domain name, potentially resulting in incorrect or failed DNS lookups.
Step-by-step explanation:
If a host name is not fully qualified, it means the host part of the domain name is not complete, potentially leading to resolution issues. A fully qualified host name includes all domain levels, ending in a top-level domain, and it uniquely identifies a host in the larger domain name system (DNS).
Without a fully qualified domain name, the system may attempt to add a local domain in an effort to complete the lookup process. If the system's DNS settings include a default domain search list, it will use this to attempt resolution. However, this can lead to incorrect or failed DNS lookups if the intended domain is outside of the local domain or if the default domain search list is not properly configured. In many cases, failure to use a fully qualified domain name will result in the system being unable to reach the intended destination on the network.