Proxmox Networking - Routed Configuration (Most secured)
Most hosting providers do not support the above setup. For security reasons, they disable networking as soon as they detect multiple MAC addresses on a single interface.
Some providers allow you to register additional MACs through their management interface. This avoids the problem, but can be clumsy to configure because you need to register a MAC for each of your VMs
You can avoid the problem by “routing” all traffic via a single interface. This makes sure that all network packets use the same MAC address.
A common scenario is that you have a public IP (assume 198.51.100.5 for this example), and an additional IP block for your VMs (203.0.113.16/28). We recommend the following setup for such situations:
auto lo iface lo inet loopback auto eno0 iface eno0 inet static address 198.51.100.5/29 gateway 198.51.100.1 post-up echo 1 > /proc/sys/net/ipv4/ip_forward post-up echo 1 > /proc/sys/net/ipv4/conf/eno0/proxy_arp auto vmbr0 iface vmbr0 inet static address 203.0.113.17/28 bridge-ports none bridge-stp off bridge-fd 0