Ubuntu 20.04 multiple IP addresses

you are absolutely right but my problem was a other one:
your file looks like this:
ethernets:
eno1:
dhcp4: no
dhcp6: no
addresses:

and I need:
ethernets:
enp4s0:
dhcp4: true
addresses:

the rest is absolutely the same but my fault was always that's I override the DHCP too...

 

If you understand ISPConfig and server stability you should know that we normaly use fixed ip for our servers so dhcp4 and dhcp6 is set to no meaning i.e. not to be automatically assigned but manually assigned.

eno1 or enp4s0 naming normally is done automatically which basically depends on your machine ethernet card that is why if you read thoroughly you have to run ip a to check and get all that basic info from your machine.

You should ask why if you are not sure but lots and lots of readings and video's watchings may help too, some times, if they did not confuse you more, that is.

 

yes... you are right... I need to learn a lot... but sometimes a stupid question to find someone that's points you in the right way is not wrong...