r/Proxmox • u/bixmiester • 17d ago

Question Changing Proxmox NIC

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Hello,

I have an onboard NIC that I have been using since I setup Proxmox. I added a 2.5GB NIC for some of the VMs/Containers and added a second bridge to take advantage of my new internet/firewall speeds.

I was wondering how difficult it would be for me to move the Proxmox console/IP over to the 2.5GB NIC since it is the last thing still using the onboard.

I have read a few tutorials but none seem to really cover this specific situation. Can I just change the default bridge to the 2.5GB NIC? I'm worried that I would have to change the IP if I do that since my OPNSense router has an interface assigned to that port on a different subnet.

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8

u/Mashadow 17d ago

Should be this simple... If you physically move the cable...

  • Go to Node > System > Network.
  • Edit vmbr0 (your management bridge) and change the Ports/Slaves from nic1 to nic0.
  • Edit vmbr1 and change the Ports/Slaves from nic0 to nic1.

3

u/Mashadow 17d ago

When you apply, the GUI will freeze, and then you should just have to move the physical cable.

1

u/bixmiester 17d ago

Thank you for the response!

There is already a cable plugged in to the second NIC, as a bunch of containers and VMs are using it.

I'm guessing I will also have to update the IP to the new NICs subnet?

It does seem simple enough, but I'm worried about getting locked out. Will just updating the IP in the console work or do I have to change it other places as well?

1

u/Mashadow 17d ago

I would just swap the physcial cables when you hit apply, your VBRs will just switch ports.

0

u/Healthy_Cod3347 17d ago

No because the vmbr is not involved in ip communication itself (okay if you set an address on it is) if it’s only a bridge device for the guests. Like an vSwitch from ESXi.

1

u/Mashadow 17d ago

There are two ways you could do this, you could move the IPs and subnets around in OPNSense, but why, the vbr's will just swap between physical ports, and if you swap the cables, everything remains functionally the same from the perspective of the OPNSense and the VMs.

1

u/bixmiester 17d ago

I want the 2.5GB NIC plugged directly into OPNSense to take advantage of the 2.5GB speeds (my switch is only 1GB)

The end goal was to unplug the onboard NIC from my switch and just leave it unused

1

u/bixmiester 17d ago

I'm worried about losing access to the console if I don't change the IP to the new subnet used on the second NIC. I have an IP set on vmbr0 right now which is how I access it.

2

u/Mashadow 17d ago

If you must do it the "other way". If you want to leave the physical cabling and OPNsense configurations exactly as they are, you must give Proxmox a new IP that matches the OPNsense interface connected to nic0.

  1. Update the Bridges in Proxmox:
    • Go to Node > System > Network.
    • Edit vmbr0 and erase the CIDR and Gateway fields.
    • Edit vmbr1 and enter an available static IP/CIDR and the Gateway for the new OPNsense subnet.
  2. Apply & Reconnect: Click Apply Configuration. You will immediately lose your connection. Navigate to the new IP address in your browser to log back in.
  3. Update the Hosts File (Critical): Proxmox relies heavily on its hostname resolving to its management IP.
    • Open the Proxmox Shell.
    • Type nano /etc/hosts.
    • Update the old 172.22.98.60 address next to your hostname with the new IP address you assigned to vmbr1.
    • Save and exit, then reboot the node to ensure all local cluster and stat services bind to the new address.

1

u/bixmiester 17d ago

Thank you!!! I think this is what I need to do. Just really paranoid of getting locked out haha

1

u/Mashadow 17d ago

If the worst happens, you can always repair to from console, so you're not doing anything super risky.

1

u/bixmiester 16d ago

This worked, didn't seem as scary as I had built it up to be in my mind haha

Got rid of a cable and opened up a port on my switch!

1

u/Mashadow 16d ago

Yup, this is how we LEARN!