A hostname is a human-readable string that helps people refer to a computer by a familiar name, rather than by a number or unwieldy descriptors like, "the third one from the bottom of the second-to-last rack." Often, a hostname is set during the installation process, but there are times when it needs to be changed. On Linux, there are many ways to set a hostname, and this article aims to cover them all.
Before exploring the tools related to hostnames, though, you must understand the different contexts in which the term is used. There are potentially two designators of a system’s hostname: the computer’s administrator (a laptop’s owner, or a server’s root user) and the network (depending on protocols and settings). This factor can lead to confusion, because you might look at your computer’s hostname and see one value, only to find that the same computer is referred to as something different over the network.
There’s a historical reason for this situation. Long ago, before DNS, hosts on a network had to be defined locally in the file
/etc/hosts. If there were 31 hosts on a network and a new one was added, then 32 hosts had to update their
/etc/hosts file to reflect the correct IP address and corresponding hostname for each of their neighbors. This process didn’t scale well for bigger networked systems such as the World Wide Web (the Internet), and so DNS was invented, and the concept of hostnames largely was abstracted away from local computers to instead be managed by the network.
Today, the important hostname is the one the network uses. The hostname value in
/etc/hosts is often set to
localhost by default.
With this context in mind, here are all the different ways to manipulate a hostname on Linux.
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Change all three names with
hostnamectl command from
systemd can manipulate three varieties of hostnames:
- Transient: Received from network configuration.
- Static: Provided by the kernel.
- Pretty: Provided by the user.
A transient hostname can change as needed to avoid name collisions. For instance, if you name your computer
penguin but there’s already another host with that name on the network, your network hostname becomes
Static and pretty hostnames are a little like local variables: They’re used for activities occurring on the local machine, mostly as a convenience for the user, along with applications that need to know whether they’re running locally or remotely (for example, over a forwarded X session).
When invoked without any arguments,
hostnamectl returns the static and pretty names, plus some system information:
$ hostnamectl Static hostname: penguin Pretty hostname: Penguin VM Icon name: computer-vm Chassis: vm Machine ID: 418d9ce8ead44bbfb6970c0d356b89bf Boot ID: fb3a310237ef41f88b1c62c26f19065a Virtualization: kvm Operating System: Fedora 30 (Workstation Edition) CPE OS Name: cpe:/o:fedoraproject:fedora:30 Kernel: Linux 5.0.9-301.fc30.x86_64 Architecture: x86-64
$ sudo hostnamectl set-hostname --pretty "Web dev test environment" $ sudo hostnamectl set-hostname --static webdev-test-env $ hostnamectl Static hostname: webdev-test-env Pretty hostname: Web dev test environment [...]
Change the static and pretty names in the GUI with GNOME Settings
If you want to set the static and pretty names in a desktop application, use GNOME Settings. To launch GNOME Settings, go to the Activities menu in the upper left corner of your GNOME desktop. Type
Settings into the search field, or click the Show Applications icon on the left dock and find Settings in the application icons as shown below:
$ hostnamectl Static hostname: rockhopper-computer Pretty hostname: rockhopper computer [...]
Change the static name with
Fedora, CentOS, and RHEL systems feature a web console application called Cockpit for monitoring and configuring local and remote machines. Using Cockpit, you can change the static hostname for your own machine, or any machine you administer (as long as it has Cockpit enabled).
First, install and enable Cockpit:
$ sudo dnf install cockpit [...] $ sudo systemctl enable --now cockpit
In the web console, click the System tab in the left column. Click the entry for Host name and edit the Pretty Host Name and (static) Real Host Name:
$ sudo echo "galapagos" > /etc/hostname $ hostnamectl Static hostname: snares Pretty hostname: rockhopper web console computer [...]
Change the static name in the
You can also set the static hostname manually by editing
/etc/hostname. This file contains exactly one line by default. If you have not changed the hostname yet, then that line probably reads
localhost.localdomain. If you have used
hostnamectl to change the hostname already, then this file reflects that change.
Editing this file manually is not necessarily recommended, because it doesn’t update all the other hostname values the way
hostnamectl does. For example:
$ sudo echo "galapagos" > /etc/hostname $ hostnamectl Static hostname: galapagos Pretty hostname: rockhopper computer Transient hostname: rockhopper-computer [...]
Change the static name with
Another way to change a static hostname is through the command line interface for Network Manager,
$ sudo nmcli general hostname emperor $ hostnamectl Static hostname: emperor Pretty hostname: rockhopper computer Transient hostname: rockhopper-computer [...]
Change the transient name with
sysctl command allows you to configure kernel parameters while Linux is running (that is, instead of at boot time). Your computer’s transient hostname is a kernel parameter, so you can modify it with this command:
$ sudo sysctl kernel.hostname=humboldt $ hostnamectl Static hostname: emperor Pretty hostname: rockhopper computer Transient hostname: humboldt [...]
Change the transient name with
hostname command from the
util-linux package is a simple tool to query and set the transient hostname.
To query your current hostname:
$ hostname humboldt
$ sudo hostname fjordland $ hostnamectl Static hostname: emperor Pretty hostname: rockhopper computer Transient hostname: fjordland
Be careful with
/etc/hosts file is mostly historic, although it is used by some applications and protocols, and can be a useful method for creating shortcuts to hosts you use often. You can use it to set a hostname, but usually, you’re just creating an alias to
localhost at IP address
127.0.0.1 (your computer’s network loopback address).
For example, if you change
/etc/hosts from the default entries like this:
$ cat /etc/hosts 127.0.0.1 magellanic magellanic.localdomain magellanic magellanic.localdomain4 ::1 magellanic magellanic.localdomain magellanic magellanic.localdomain6
$ ping -c 1 localhost PING localhost(magellanic (::1)) 56 data bytes 64 bytes from magellanic (::1): icmp_seq=1 ttl=64 time=0.182 ms [...] $ ping -c 1 magellanic PING magellanic(magellanic (::1)) 56 data bytes 64 bytes from magellanic (::1): icmp_seq=1 ttl=64 time=0.181 ms [...]
$ hostnamectl Static hostname: emperor Pretty hostname: rockhopper computer Transient hostname: fjordland
Follow the conformity convention
As you can tell from the iterations within this article, a computer’s hostname can get confusing should you use too many methods to set it, or if you change it frequently. While nothing enforces uniformity across hostname types, it’s a convention to keep everything the same on each computer.
Choose a memorable name and use it for your pretty name. Let the static and transient names be derived from that. Just as importantly, in a large network, choose meaningful names. For instance, all upper management computers may be named after a D&D monster, while all computers in the IT department may be named after a famous starship, and so on. Using a naming schema helps avoid name collisions and provides context to an otherwise dizzying list of network hosts.