Add a new nic card, ip link shows the old nic name changed, but /etc/network/interfaces still uses old name.

[prolab]

My motherboard originally only have one RJ45 network port. After installed Proxmox VE, ip link shows its name was enp5s0.

Then later I added a new pci-e network card with two SFP+ ports. Then I found I can't access the Proxmox VE server's management interface through the old port. Since it's running as a server without monitors connected, I have to connect a keyboard and monitor to it to figure out why. Then I found after added the new card, ip link shows the old port's name has changed to enp6s0 (the two new nic names are ens6 and ens6d1). But /etc/network/interfaces still uses the old name enp5s0 which does not exist anymore. After changed the name, the problem is resolved.

This causes a bit of trouble and if the added pci-e card fails someday the nic name may be changed back. So I'm wondering can we let /etc/network/interfaces automatically detect and change its name? Or can we use something fixed like MAC address so we do not need to worry about the name changes anymore?

 

[Stefan_R]

/etc/network/interfaces is a static configuration file, it would be a bad idea to auto-update it. In theory, the "predictable" systemd network names shouldn't change anyway, that's more a side-effect of hardware being quirky and only barely holding together at all.

You can however assign a custom name to a network interface, matched by MAC address (or several other properties). See here for more, example configuration:

# cat /etc/systemd/network/10-onboard.link
[Match]
MACAddress=xx:xx:xx:xx:xx:xx
[Link]
Name=customname0

You'd have to change 'enp6s0' to 'customname0' in /etc/network/interfaces, but from then it shouldn't change again.