network configuration

guthrie · 11-11-2022, 10:35 PM

I have a new install of Debian 5.10, and all works fine, but I want to convert from DHCP to a static IP.
I think I know all the details (!) of how to do this - but in my /etc/network/interfaces.d/setup file it declares:
"iface etho inet dhcp"
But all of the other tools (ip, nmcli, lspci) show that the network interface is enp4s0.

I understand that on boot is is supposed to be changed, and indeed dmesg shows:
"enp4s0 renamed from eth0"

trying: systemctrl status networking
fails; saying "Cannot find device etho".
(before I made any changes)

I tried changing /etc/network/interfaces.d/setup to use enp4s0 instead of the original installation eth0, no effect.

What to do? And why is the setup as installed not valid with the systemctrl check?

mrmazda · 11-11-2022, 11:24 PM

You can force your ethernet interface to keep the traditional name eth0 by including on your kernel command lines in grub.cfg and /etc/default/grub net.ifnames=0. You can configure static IP using systemd using systemctl to disable whichever network system (and automatic resolver) is in control, enabling systemd-networkd instead, and creating /etc/systemd/network/eth0.network containing its configuration:

Code:

[Match]
Name=eth0

[Network]
Address=###.###.###.###/24
DNS=###.###.###.### [###.###.###.###] [###.###.###.###]
Gateway=###.###.###.###
IPv6AcceptRA=no
LinkLocalAddressing=no

Finish up by creating a static /etc/resolv.conf and uninstalling or otherwise disabling whatever was automatically generating it, e.g. resolvconf package. More detail here.

michaelk · 11-12-2022, 03:29 AM

The kernel version is 5.10, the debian version is 11 aka bullseye.

If you are running a desktop the easiest way is to use the networking manager applet i.e. the network icon in the upper right, select network settings and switch to a static ip address. If not using a desktop use the nmcli utility.

Networking is controlled by network manager versus the traditional networking scripts by default unless you switch back.