When I run
ifconfig -a, I only get lo and enp0s10 interfaces, not the classical eth0
What does enp0s10 mean? Why is there no eth0?
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Answer on "What does enp0s10 means?" question:
enp0s10: | | | v | | en| | --> ethernet v | p0| --> bus number (0) v s10 --> slot number (10)
Source: udev-builtin-net_id.c on GitHub
That's a change in how now udevd assigns names to ethernet devices. Now your devices use the "Predictable Interface Names", which are based on (and quoting the sources):
- Names incorporating Firmware/BIOS provided index numbers for on-board devices (example: eno1)
- Names incorporating Firmware/BIOS provided PCI Express hotplug slot index numbers (example: ens1)
- Names incorporating physical/geographical location of the connector of the hardware (example: enp2s0)
- Names incorporating the interfaces's MAC address (example: enx78e7d1ea46da)
- Classic, unpredictable kernel-native ethX naming (example: eth0)
The why's this changed is documented in the systemd freedesktop.org page, along with the method to disable this:
ln -s /dev/null /etc/udev/rules.d/80-net-setup-link.rules
or if you use older versions:
ln -s /dev/null /etc/udev/rules.d/80-net-name-slot.rules
As mentioned above, enp0s10 refers to ethernet (en), prefix 0 (p0), slot 10 (s10).
The bus number, device number, and function number are pulled from the Bus Device Function (BDF) notation for PCI devices to create the prefix, slot, and function portions of the Predictable Network Interface Name (PNIN).
If the function is 0, the f0 portion is sometimes omitted. I changed the prefix from p0 to p4, and the function from f0 to f1, for clarity in this example. BDF uses hex values which get converted to decimal values in the PNIN.
enp4s10f1 pci 0000:04:0a.1 | | | | | | | | | | | | domain <- 0000 | | | | | | | | | | en| | | --> ethernet | | | | | | | | | p4| | --> prefix/bus number (4) <-- 04 | | | | | | s10| --> slot/device number (10) <-- 10 | | | f1 --> function number (1) <-- 1
I came across a device with a u7 at the end, for USB port. Some of the different label possibilities are included in this documentation on predictable network interface device names.
A second example for the case where the PCI domain is something other than 0 (P stands for PCI geographical location):
P1enp4s10f1 pci 0001:04:0a.1 | | | | | | | | | P1| | | | --> PCI geo loc/domain <-- 0001 | | | | | | | | | | en| | | --> ethernet | | | | | | | | | p4| | --> prefix/bus number (4) <-- 04 | | | | | | s10| --> slot/device number (10) <-- 10 | | | f1 --> function number (1) <-- 1
To quote the full text on disabling linked by @Braiam:
I don't like this, how do I disable this?
You basically have three options:
- You disable the assignment of fixed names, so that the unpredictable kernel names are used again. For this, simply mask udev's .link file for the default policy:
ln -s /dev/null /etc/systemd/network/99-default.link
- You create your own manual naming scheme, for example by naming your interfaces "internet0", "dmz0" or "lan0". For that create your own .link files in
/etc/systemd/network/, that choose an explicit name or a better naming scheme for one, some, or all of your interfaces. See
systemd.link(5)for more information.
- You pass the
net.ifnames=0on the kernel command line
TL;DR: it has been renamed to