How to change network interface policy on Ubuntu/Debian/RHEL/CentOS/Fedora/Rocky Linux

The predictable network interface name is:

1. Stable after restart
2. Fixed/consistent even when hardware is added or removed
3. Fixed/consistent even after defective/damaged hardware was replaced
4. Stateless, no explicit configuration file required

To ensure system security and ease of use of network interfaces, predictable network interface names are crucial. For this reason, mainstream Linux distributions often use "systemd" and "udev" to assign predictable names to the computer's network interfaces. This makes it easier for users to manage and identify individual network interfaces, while also contributing to system stability and performance optimization. In this way, users can configure and manage the network more conveniently, improving overall system operation efficiency and security.

Currently, there are some network interface naming strategies that can be used on Ubuntu, Debian, RHEL, CentOS, Fedora, Rocky Linux and other popular Debian/Ubuntu-based or RPM-based Linux distributions. In this article, we will discuss the network interface naming strategies available in Linux and show you how to switch to the one you want.

Content topic:

1. Available network interface removal policies
2. Currently used network interface deletion policy
3. Change network interface deletion policy
4. Check if the new network interface removal policy is being used
5. Configure a custom name for the network interface
6. in conclusion

Available network interface removal policies

Currently, the available network interface naming strategies are:

1. Kernel - In this policy, the kernel does not rename predictable network devices, i.e. lo (loopback interface)
2. Database - In this policy, the udev hardware database "hwdb" is used to assign network device names.
3. Onboard—In this strategy, the index numbers provided by your computer's BIOS/firmware are used to name the onboard network devices, i.e. eno1, eno2.
4. slot—In this strategy, the PCIE hot-plug slot index numbers provided by the computer BIOS/firmware are used to name the network devices, i.e. ens1, ens2.
5. Path - In this policy, the network devices are named using the physical location of the hardware, i.e. enp1s0, enp1s2, enp1s0f0, enp1s0f1.
6. mac—In this policy, the mac address of the network device is appended to the network interface name, which is enx000c294cd7e8.

Currently used network interface deletion policy

The default network interface naming policy configuration file on most popular Linux distributions is located in the "/usr/lib/systemd/network/99-default.link" path.

You can use the nano text editor to open the default network interface naming policy configuration file "/usr/lib/systemd/network/99—default.link", as shown below:

$sudo nano/usr/lib/systemd/network/www.example.com

The order of network interface naming policies to be used is listed in the "NamePolicy" section [1].

Here, "Hold" has the highest priority. systemd/udev will use the same name over and over again as long as that name has been assigned to the network interface.

It will then try to set the kernel name. If the kernel naming policy fails, database, onboard, slot, and path are used respectively.

You can also set alternative names for network interfaces in the same way using the "AlternativeNamesPolicy" option [2]. Naming policies that are not used for actual network interface naming are used as alternative naming policies, depending on the order set in "AlternativeNamesPolicy".

As you can see, by default, the slot network interface naming policy is used to name the actual network interface, and the path network interface naming policy is used to provide alternative names for network interfaces on Ubuntu 22.04 LTS. Other Linux distributions may use different naming strategies and alternative naming strategies by default.

$IP a

Change network interface deletion policy

To change the network interface naming policy, please use the nano text editor to open the "/usr/lib/systemd/network/99—default.link" configuration file, as shown below:

$sudo nano/usr/lib/systemd/network/www.example.com

Type the desired network interface naming policy in the "NamePolicy" section and the alternative network interface naming policy in the "AlternativeNamePolicy" section.

When finished, press X, then "Y" to save the "99—default.link" file.

For the changes to take effect, please restart your computer as follows:

$sudo reboot

Check if the new network interface removal policy is being used

After the computer boots, run the "ip" command to verify that the network interface name has changed accordingly. As you can see, the Mac network interface naming policy is used to set the real name of the network interface, and the PATH network interface naming policy is used to set the alternative name of the network interface.

$IP a

In this example, we use the path naming strategy for the real name and the mac naming strategy for the alternative name of the network interface.

Configure a custom name for the network interface

In addition to using the predefined network interface naming strategy, you can also set a custom name for your computer's network interface. To learn how to set a custom name for a network interface, read this article.

in conclusion

In this article, we discussed the network interface naming strategies available with modern Linux distributions. We also show you how to use different network interface naming strategies on Ubuntu/Debian, RHEL/Rocky Linux/CentOS/Fedora, and other modern Ubuntu/Debian-based or RPM-based Linux distributions.

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