Interface not automatically UP after power on and replug

[eiger3970]

I installed Proxmox 6.3.
However, I notice the Ethernet interface is DOWN after powering on the hypervisor machine.
I have unplugged the cable sometimes, other times the Ethernet cable stayed plugged in.
I can easily change the interface status with

ifup <interfaceName>

However, when I move the hypervisor machine to its storage location, there will be no monitor and keyboard plugged in.
How can I ensure the interface is UP or automatically change status to UP after I move the machine to storage, plug Ethernet in and power up?

 

[fabian]

you need to mark the interface as "auto" for it to be brought up on boot. if it doesn't come up even though it is set, please check the journal for errors related to bringing network interfaces up..

 

[eiger3970]

Fixed.
I added line:

auto <interfaceName>

Surprised the new Proxmox install does not have that line, unless I accidentally deleted it.
Possible, as I'm editing the file, as I haven't solved Wi-Fi PCIe NIC install on Proxmox or cabled Ethernet Internet from machine with Internet to Proxmox machine.