Where is interfaces file on the Debian 12?

[Nanja]

I want to be able to ping my extra IP's before I start working on Proxmox in Debian 12.
I can't even ping the extra IP's because I can't add them...
All tutorials say to edit interfaces, but interfaces is completely empty in Debian 12?

What is the correct file to edit my interfaces?? Since /etc/network/interfaces does not work.

So basically, my

/etc/network/interfaces

is empty...
It shows this

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

When I do

root@dedi:~# ip -c link show

The result is this

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eno2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
    link/ether 0c:c4:7a:94:28:cd brd ff:ff:ff:ff:ff:ff
    altname enp2s0
3: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 0c:c4:7a:94:28:cc brd ff:ff:ff:ff:ff:ff

When I do

root@dedi:~# ip -c addr show enp0s31f6

The result is this

3: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 0c:c4:7a:94:28:cc brd ff:ff:ff:ff:ff:ff
    altname enp0s31f6
    inet 104.128.**.**/24 brd 104.128.58.255 scope global noprefixroute eno1
       valid_lft forever preferred_lft forever
    inet6 fe80::ec4:7aff:fe94:28cc/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

It shows that I have IP setup and valid working network, but why aren't they in the interfaces file?

 

[B.Otto]

Maybe your Debian is using NetworkManager instead of the interfaces file? Can you run nmtui?