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How to give a name to a specific interface in a local network? (Ubuntu 20.04)

cn flag
JYF

I am currently trying to set up (as a total noob) a small home server running Ubuntu 20.04. The server is a Minisforum mini PC (U820 model) with two Ethernet ports. The first port is connected to my ISP fibre box. The second port is connected to my usual everyday computer, a Mac — so the Ubuntu server is some kind of router. The Mac is also wirelessly connected to the server (as I activated wifi sharing in Ubuntu).

On the Ubuntu terminal, the ip a command originally told me to use the 10.42.0.1 address to locally access the server via Ethernet from the Mac:

3: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 5c:85:7e:4e:6c:e5 brd ff:ff:ff:ff:ff:ff
    inet 10.42.0.1/24 brd 10.42.1.255 scope global noprefixroute enp2s0
       valid_lft forever preferred_lft forever
    inet6 fe80::1ea8:95f4:8840:fee/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
4: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether b0:a4:60:7c:c0:a4 brd ff:ff:ff:ff:ff:ff
    inet 10.42.1.1/24 brd 10.42.0.255 scope global noprefixroute wlp3s0
       valid_lft forever preferred_lft forever
    inet6 fe80::d87f:88e4:afe7:637f/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

But recently (after an Ubuntu reboot?) the local addresses changed, they were reversed, now I have to use the address 10.42.1.1 to connect to the server via the Ethernet port.

How can I prevent future reversals? Or is it possible to give some name to the enp2s0 Ethernet interface, a name that could be used from the Mac to always connect to the server through the wired path?

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user535733 avatar
cn flag
user535733
`enp2s0` is the consistent name of one of your ethernet interfaces. See https://netplan.io/examples/ for examples of how to use that consistent name to set up your networking properly.
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cn flag
JYF
Thanks for your answer, but the netplan.io/examples page is too difficult for me. How can I connect from my local computer to the server via Ethernet using a command like `ssh myname@enp2s0` or `ssh myname@server-via-cable`? How can I set a permanent name for the Ethernet interface, recognizable by any other computer on the local network?
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user535733 avatar
cn flag
user535733
The only kind of "*permanent name for the Ethernet interface, recognizable by any other computer on the local network*" is an IP address. Other machines do not know your system's ethernet port names. They only know your system's IP address. (That's why it's called an *address*). There are other methods of spotting machines and services on a local network, but they are all tied to that IP address.
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