Proxmox with multiple IP same subnet — just add it to the bridge

Proxmox with multiple IP same subnet is dead simple — you just slap the extra IP onto the bridge interface in /etc/network/interfaces. No VLANs, no routing tricks, no separate bridges. Here's the config that actually works on Proxmox 8.

Why the hell would you need this?

Maybe you're running multiple services that each want their own public IP. Maybe you're migrating stuff and need both old and new IPs live at once. Whatever the reason, adding a secondary IP to your Proxmox host in the same subnet is a basic thing that the docs somehow make look harder than it is.

The config that works

Open up /etc/network/interfaces. You'll see your existing bridge — probably vmbr0. Just add another address line under it. Like this:

auto vmbr0
iface vmbr0 inet static
    address 192.168.1.10/24
    address 192.168.1.11/24
    gateway 192.168.1.1
    bridge-ports eno1
    bridge-stp off
    bridge-fd 0

That's it. Two IPs on the same bridge, same subnet. No separate virtual interface needed. Proxmox handles it fine — the kernel just adds the second IP as a secondary address on the bridge.

Apply it without rebooting

Don't reboot the whole damn server. Just restart networking:

systemctl restart networking

Or if you're paranoid, bring the bridge down and up:

ifdown vmbr0 && ifup vmbr0

Then check with ip addr show vmbr0. You should see both IPs listed.

If it doesn't work right away

Sometimes the secondary IP doesn't respond to pings immediately. Give it a minute, or flush the ARP cache on your router. Also make sure your gateway isn't doing anything stupid like blocking multiple MACs on the same port — most home routers don't care, but some managed switches might.

If you're messing with IPs on a VM instead of the host, the concept is the same — just add the second IP inside the VM's network config, not on the Proxmox host. But for the host itself, this is all you need.

And if you're doing this because you're migrating services, check out how to get a VM's IP without the guest agent — saves you from logging into every VM just to see what IP it grabbed.