Computer Name Resolution

Remembering IPv4 addresses can be cumbersome, especially when there are many machines on many networks. One way we sort out this complexity is with the use of the Domain Name System (DNS). When one computer connects to another computer using its domain name, the DNS translates the computer’s domain name into its appropriate IP address.
The DNS will first access a network-based file called the hosts file. The hosts file is a listing of corresponding IPv4 addresses and host names. By default, there is only one IP address—the localhost address; it is equivalent to the loopback address 127.0.0.1. The hosts file can always be modified to accommodate additional IP addresses.
If it has not found the IP address in the hosts file, the computer will need to query the DNS cache (on Windows machines) and then the DNS server for the IP address. The DNS cache is a local copy of recently used name–IP address pairs. If the name is not in the cache, then the request is directed to a DNS server. If the DNS server does not have the IP address in its database, it can “ask” another DNS server for the information. DNS servers are organized in a hierarchical structure, ultimately ending at servers maintained by the naming authorities. This is an efficient method of resolving IP addresses to names.
The fully qualified domain name (FQDN) is a dot-separated name that can be used to identify a host on a network. The FQDN consists of the host name along with its domain name and any other subdomain names, such as www.somename.com.
In this lab, you will modify the hosts file, test connectivity using the FQDN, and then explore the functionality of the nslookup command