Multiple NIC bridging/routing


New Member
Dec 29, 2018
(Please see attached image)

I have a single host with four interfaces (2x 1Gb, 2x 10Gb).
eno0 is used for the external nat/route to the upstream firewall and external access via
eno1 is not currently used, but *will* be used as a 1Gb guest bridge into a switch (10.0.30.x)
enp2s0f0 and f1 are 10gb ports into two different uplink switches (10.0.10.x, 10.0.20.x)

What I don't understand how to do in the proxmox environment is to set up route/NAT so that the guest machines in 10.0.x.x (10.x, 20.x, 30.x) will have a gateway interface (10.1, 20.1, 30.1) to:

1. Allow them to communicate between network segments like 10.x <=> 20.x
2. Allow them to communicate uplink like 10.x <=> 10.1 which NAT/route to eno0 (


Is there a guide anywhere on how to do this kind of thing? I am new to Proxmox, but I have worked in VMWare before and I'm familiar with basic networking.

Thanks in advance for any help provided.
Also, I'm wondering if people would recommend using the VSwitch OVS stuff instead of the native layer.
for NAT you can use
auto vmbr192

iface vmbr192 inet static
        bridge-ports none
        bridge-stp off
        bridge-fd 0

        post-up echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up   iptables -t nat -A POSTROUTING -s '' -o vmbr0 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '' -o vmbr0 -j MASQUERADE

and for the 10. bridges you could bond all the LAN NIC's

auto bond0
iface bond0 inet manual
    slaves enp2s0f0 enp2s0f1 eno2
    bond_miimon 100
    bond_mode broadcast

auto vmbr10
iface vmbr10 inet static
        bridge-ports bond0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094

hope this helps
Also, I'm wondering if people would recommend using the VSwitch OVS stuff instead of the native layer.

then you may wanna read what OVS can do.
when you create a bridge its basically a stupid switch, that kinda supports vlan and thats about it.

OVS is kinda a smart switch that let you isolate certain ports, port mirror,qos, and so on.
i woudl actually love to see OVS nativly implemented into promox with config over its api (for automisation)

without OVS you have noi clue or control whats happening on a vmbridge (well not much anyway).


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