fcc95ff817
This allows for correct highlighting and maybe future automatic formatting. The AST was verified to work with nixfmt only.
56 lines
1.8 KiB
Markdown
56 lines
1.8 KiB
Markdown
# Renaming network interfaces {#sec-rename-ifs}
|
|
|
|
NixOS uses the udev [predictable naming
|
|
scheme](https://systemd.io/PREDICTABLE_INTERFACE_NAMES/) to assign names
|
|
to network interfaces. This means that by default cards are not given
|
|
the traditional names like `eth0` or `eth1`, whose order can change
|
|
unpredictably across reboots. Instead, relying on physical locations and
|
|
firmware information, the scheme produces names like `ens1`, `enp2s0`,
|
|
etc.
|
|
|
|
These names are predictable but less memorable and not necessarily
|
|
stable: for example installing new hardware or changing firmware
|
|
settings can result in a [name
|
|
change](https://github.com/systemd/systemd/issues/3715#issue-165347602).
|
|
If this is undesirable, for example if you have a single ethernet card,
|
|
you can revert to the traditional scheme by setting
|
|
[](#opt-networking.usePredictableInterfaceNames)
|
|
to `false`.
|
|
|
|
## Assigning custom names {#sec-custom-ifnames}
|
|
|
|
In case there are multiple interfaces of the same type, it's better to
|
|
assign custom names based on the device hardware address. For example,
|
|
we assign the name `wan` to the interface with MAC address
|
|
`52:54:00:12:01:01` using a netword link unit:
|
|
|
|
```nix
|
|
{
|
|
systemd.network.links."10-wan" = {
|
|
matchConfig.PermanentMACAddress = "52:54:00:12:01:01";
|
|
linkConfig.Name = "wan";
|
|
};
|
|
}
|
|
```
|
|
|
|
Note that links are directly read by udev, *not networkd*, and will work
|
|
even if networkd is disabled.
|
|
|
|
Alternatively, we can use a plain old udev rule:
|
|
|
|
```nix
|
|
{
|
|
boot.initrd.services.udev.rules = ''
|
|
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", \
|
|
ATTR{address}=="52:54:00:12:01:01", KERNEL=="eth*", NAME="wan"
|
|
'';
|
|
}
|
|
```
|
|
|
|
::: {.warning}
|
|
The rule must be installed in the initrd using
|
|
`boot.initrd.services.udev.rules`, not the usual `services.udev.extraRules`
|
|
option. This is to avoid race conditions with other programs controlling
|
|
the interface.
|
|
:::
|