Setup a secondary IP

make your host available on a specific alternative IP address - chatGPT

Ubuntu 22+ / Debian 12

list all network interface (even unconnected) ls /sys/class/net or ifconfig -a

Check if you are using netplan or NetworkManager cat /etc/netplan/1-network-manager-all.yaml => default to NetworkManager

NetworkManager

this is dependant of the interface: changing a usb dongle will hide it.

$ nmcli connection show
# You'll see something like: NAME: Wired connection 1 ... DEVICE: enp0s3
# if nothing => probably not using NetworkManager.

# Add the alternative IP
$ sudo nmcli connection modify "Wired connection 1" +ipv4.addresses 192.168.0.134/24

# Ensure manual addressing is enabled (alongside DHCP):
$ sudo nmcli connection modify "Wired connection 1" ipv4.method auto

# Apply change
$ sudo nmcli connection down "Wired connection 1" && sudo nmcli connection up "Wired connection 1"

# Check your IPs:
$ ip addr show enp0s3

Netplan

cat /etc/netplan/xx.yml

see ChatGPT

Written on May 10, 2025, Last update on May 16, 2025

network linux-system