Multiple IPs on one NIC with bridges

JamesMio

New Member
Oct 15, 2017
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I located my own Hardware in a Data Center. Then I tried to setup bridged network for multiple VMs.

The environment specified multiple IP addresses.
First available IP address for my server is: xx.xxx.xx.194
IP Range is: xx.xxx.xx.194 - xx.xxx.xx.20x
Gateway is: xx.xxx.xx.193
Netmask: 255.255.255.240
PROXMOX Version: 5.0-23/af...

Now I planned to assign xx.xxx.xx.194 to proxmox and all the others to the planned VMs.

I configured everything through proxmox GUI. But on guest VM (Ubuntu 16.04) I can't reach any outside host and even not proxmox host.

Below is my setup in proxmox.
I hope there is an easy solution to fix my setup.

Code:
auto lo
iface lo inet loopback

auto eno1
iface eno1 inet static
        address  xx.xxx.xx.194
        netmask  255.255.255.240
        gateway  xx.xxx.xx.193
#Public Uplink

auto vmbr195
iface vmbr195 inet static
        address  xx.xxx.xx.195
        netmask  255.255.255.240
        bridge_ports eno1
        bridge_stp off
        bridge_fd 0

auto vmbr196
iface vmbr196 inet static
        address  xx.xxx.xx.196
        netmask  255.255.255.240
        bridge_ports none
        bridge_stp off
        bridge_fd 0
 
hi james
bridge setup does not work like this
you need only one bridge vmbr0 (our default setup ) which is like a virtual switch.
then when creating your VMs, you add their NICs to vmbr0, similar to pluging the cable in the virtual switch

IP address configuration is done inside the guest, not in the host
 
@JamesMio
Did you figure out the configuration? I have the same issue. Does your host provider allows multiple MAC addresses?
Hi @New User I'm right now not sure if the solution from @manu works. I made a mistake during reconfiguring as @manu suggested. So now I need to get my hands on the server to fix the setup. I hope to manage it this week. Once I made it I will report my solution.

To answer your question @New User my hosting provider allows multiple MAC addresses. If you are not in favour of this environment, there are other solutions for those situations. I read a lot about those during investigating the internet for a working setup for my environment.

My network config as of @manu 's suggestion will look like follows:
Code:
auto lo
iface lo inet loopback

auto eno1
iface eno1 inet static
       
auto vmbr0
iface vmbr0 inet static
       address  xx.xxx.xx.194
       netmask  255.255.255.240
       gateway  xx.xxx.xx.193
       bridge_ports eno1
       bridge_stp off
       bridge_fd 0
#Public Uplink

Remember those things:
  • eno1 is my hardware NIC and my only connected cable to the hosting providers network (routed to public IPs)
  • all of my VMs will use the one and only available bridge: vmbr0
  • every VM will have it's own static setup to register the other IP addresses each with it's own MAC address
 
Last edited:
@JamesMio thanks for letting me know. I'm trying to figure out the same thing but without MAC addresses assigned to Public IPs. If you could post the working setup here that would be awesome. Also, are you CentOS 7 for any of VM by any chance?
 

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