What is a Hostname?

In a network, a hostname is a unique name of a computer or device (host). It is also known as a computer name, site name, or node name, which identifies a hardware device or host on the network. Hostnames are used in the local area network. And like the internet, they are also used in wide area networks (WANs). Hostnames are the collection of character strings or specific names which them unique and usable for the network and people. Also, both network nodes and physical addresses can be described by hostnames, which contain different domains under one host.

The same principle applies to the WWW (World Wide Web), where hostnames are transformed into IP addresses using a domain name system, which provides a one-to-one description to all users, whether they be web servers, computers, or network nodes at the Internet provider.

Hostnames used for the local network cannot have spaces and special characters, such as apostrophes, periods, and commas; however, they do not contain a standard format. For instance, if your name BoB, "Alice's iBoB", the hostname for this name will automatically be "Alices-iBoB.local". You can customize your computer's hostname if you are a Mac user. The hostname can be customized with the help of changing the computer name in the Sharing System Preference. The Windows PC users can also customize their hostname with the help of modifying the computer name in the System Control Panel.

Internet hostnames are simply referred to as domain names, for example, javatpoint.com. Typically, they are fully qualified domain names, like www.javatpoint.com or php.javatpoint.com, as all subdomain is different hostnames. However, a domain prefix like "www" is not included within a website URL; the domain name can work as the hostname.

Hostnames are translated into IP addresses with the help of using domain name systems in the local networks and wide area networks like the Internet. Each host name is mapped to a unique IP address by a local or remote DNS server, through which the device is identified on a network. Therefore, hostnames make it easy to remember websites on the Internet and names of devices on a network as they are simply used as human-readable labels.

Furthermore, in the Internet architecture, hostnames are between domain names and IP addresses. It had a relay function, which was replaced by domain name system. Historically, for IP addresses, hostnames were a name resolution. In the root directory of a computer, the hostname for the local address and the IP address of the system can generally still be found. With the host name, the name resolution can nevertheless be managed if the domain server is not reachable.

How hostname works

The main objective of the domain name system is to make easier use of the internet for users. With the help of exchanging data between IP addresses, computers include communication in various ways. However, in a system, the role of a network cannot be accessible with the help of an IP address. Also, the hostname is generally specified in the local host or host file; hence, it is assigned to find the interface.

Hostnames are used by different kinds of services in the network, like data transfer protocols or a mail server to assign the roles in a network, so that the communication of network users can be enabled. Furthermore, interfaces or the computers can be addressed and know their roles in the system via hostnames.

Guidelines on hostnames

Hostnames must meet different requirements in order to meet international standards on the basis of the network type used and the network protocol.

• Private networks: In Local area networks, VPN, and the internet, the hostnames can be assigned freely. You only need to follow the restrictions of the protocol used. Also, with the WWW, for example, TCP / IP and HTTP, the same protocols are usually used. Other protocols may be related on the basis of the network. For instance, when data is transported through TCP, the RFC 5966 protocol is used, and RC 5321 is used for transferring emails. In private networks, domain names can be omitted.
• Public networks: Also, hostnames are limited to the internet restricted to Internet protocols on the world wide web. As early as 1989, the document RFC 953 was replaced by the protocol RFC1123. In order to reach publicly accessible machines on the network, hostnames are usually registered as fully qualified domain names, which facilitates direct resolution to an IP address.

Hostnames can begin with a letter or a number and contain characters from the ASCII character set, which includes the numbers 0 through 9, the letters A through Z, and the hyphen sign. The hostnames are separated with periods. A label is called whatever is located between the periods. Each label contains from 1 character to up to 63 characters. The label cannot begin and end with a hyphen. A hostname, in general, can have a maximum of 255 characters. Usually, if the hostname is part of a domain name and does not match, it indicates the use of the network instance.

Hostname rules and restrictions

There are some rules and restrictions for the hostname that have to follow to make a valid hostname.

• A hostname does not contain space; it must be a single word.
• The numbers, letters, hyphens, or periods may use to create a valid hostname.
• The 253 characters are the maximum length for a hostname.
• With the hostname, a DNS name may be enclosed.
• An underscore cannot be used with the hostname. However, an underscore may be used with an appended DNS to the hostname.
• The hostname should not be begun with a hyphen character or a number; it is required by early hostname specification in RFC 952. However, later in RFC 1123, this restriction was changed.

Uppercase or lowercase characters can also be used in hostname. However, some systems and tools consider everything lowercase as they ignore cases. Additionally, it will be better to use lowercase characters in hostnames, which may help you out with any possible problems or confusion.

What should be used "host name" or "hostname" in writing?

On a network, "hostname" should be written as one word when referring to a computer, and it does not have space unless referencing a product, which makes use of the two-word form.