What is Hostname Resolution?

Instructor: Temitayo Odugbesan

Temitayo has 11+ years Industrial Experience in Information Technology and has a master's degree in Computer Science.

Hostname resolution makes it easy to locate a system on a large network. In this lesson, we will see what Hostname Resolution is all about and how a System Administrator would make use of it.


The hostname is a unique identifier assigned to a computer system (host) on a network with which it can be identified and accessed easily. Simply put, it is the computer system's name or an alias or domain name.

Johnson works for a Fortune 500 company on Walls Street as a trainee Systems Administrator. The office setting is made up of about five departments with each having at least ten staff members and with this workers comes a large number of computer systems to manage and administer.

Sitting at his desk in front of his network monitoring tool console, Johnson could only see assigned IP Addresses of the systems (served by the DHCP Server gateway to which they are connected to) and he has no way of knowing which system belongs to what department or staff.

Each time he wants to administer any of the systems in particular, he needs to go down to the floor where it is located, copy out its IP Address and return back to his workstation. This is taking its toll on his productivity.

It's time for Johnson to learn about hostnames.

Hostname Configuration and Uses

Every computer system can have a host configured. On Windows-based hosts for example, the configuration is carried out by updating the system's hosts file which exists in the ''SYSTEM32\DRIVERS\ETC'' directory under the Windows root directory (i.e., \WINDOWS or \WINNT). This may however change depending on the version of the Windows operating system running.

UNIX/Linux based systems also use the host file for the configuration of the hostname, sometimes located in ''/etc/hosts''.

In either instance, the host file entry is made in the following format:


Armed with this information, Johnson proceeds to configure the computer systems in his office. He does this by designing a naming pattern specific to each department.

With the hostnames configured, Johnson is now able to see the names on his screens, rather than the IP Addresses of the computers in the departments. This makes it easier for him to identify hosts on his network.

Being a curious trainee, Johnson researches how the network is able to identify a hostname and direct his network request to the particular host.

He discovers that each time he sends a network request from his computer systems named ''NetAdm1'' to access, for example, a computer host named ''SalesDesk1'' (belonging to the Sales department), the request is announced on the network to all connected systems and references their respective ''host files'' for any that has ''SalesDesk1'' configured. The network request is sent to this host and in turn it responds back, formally opening up communication with the request sender. What Johnson just discovered is hostname resolution.

Hostname Resolution

Hostname Resolution refers to the process through which an assigned hostname is converted or resolved to its mapped IP Address so that networked hosts can communicate with each other.

This process can either be achieved locally on the host itself or remotely through a designated host configured to serve that purpose.

Local Hostname Resolution

Locally on the host, there exists a host configuration file (host file) on which the IP Address and hostnames are entered. Entries in this file would like:


The IP address precedes the hostname which in this case is represented by ''localhost '' and ''netadm''.

In this example however, the host on which the file is located is called ''localhost ''. This is a standard in all computer systems and it simply refers to itself. The entries for ''netadm1'' resolve on the same network or remotely. The advantages of having the hostname resolved locally is that it allows the user customize it at any time.

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