Dual homing with two NICs (Different newtorks and two different gateways)

[rfox]

Hello to all - I'm new here, so please be gentle!

I just set up my first "real" Proxmox server - with proper "server grade" hardware for a home lab setup (after testing it on an old PC) - I installed it on top of a baseline Debian 10 to start with . . . and setup several containers and VMs already - main goal was to replace my older QNap NAS and have a stronger platform for VM & CT stuff . . .

Also a great way to learn new stuff!! My present challenge is as follows:

I have two separate networks with their own gateways to different internet connections - My server has dual NICs and I have configured them to be on the perspective networks (192.168.10.0/24 and 192.168.30.0/24) - although the Proxmox interface only allows one GW setup. I'd like to set it up using metrics and round robin with dual homing GWs - when I created a LinuxMint VM and gave it both networks using the virtual brigdes - the NetworkManager within the VM set things up with dual GWs (see attachment)

Because ProxMox doesn't use NetworkManager's magic, and I know it's technically possible in Linux - I'm not sure how to change this on the Proxmox server without breaking something (especially the UI) - The advanage of this type of config is to have a fallback Internet connection if one dies . . .

Any hints would be welcome !!

Thanks in advance & Stay Safe! - R.Fox

 

[Dunuin]

I would recommend you try to virtualize a OPNSense. OPNsense can act as your router/firewall and is supporting multiple subnets, multiple gateways, failover and so on. That way you could create serval isolated DMZ subnets for your VMs and you can create rules like "everything from subnet X uses gateway A only", "everything from subnet y uses gateway B only" or "everything from subnet Z may use gateway A+B"
That way you just need to point to the OPNsense VM as your gateway and OPNsense will take care of the routing.

 

[rfox]

I would recommend you try to virtualize a OPNSense. OPNsense can act as your router/firewall and is supporting multiple subnets, multiple gateways, failover and so on. That way you could create serval isolated DMZ subnets for your VMs and you can create rules like "everything from subnet X uses gateway A only", "everything from subnet y uses gateway B only" or "everything from subnet Z may use gateway A+B"
That way you just need to point to the OPNsense VM as your gateway and OPNsense will take care of the routing.

Thanks for the quick response! I was contemplating using OPNSense - but it adds another layer of complexity and another tool to learn OPNSense is quite powerful (experimented a bit with it) - but overkill for my scenario - and eats more precious resources from my shiny new server!

If I can get the Proxmox (Debian) host to configure like the LinuxMint guest VM I'd be a happy camper . . .

Cheers,
R.Fox

 

[rfox]

I found this article which seems to show an alternative way to achieve the same goal: https://www.thomas-krenn.com/en/wiki/Two_Default_Gateways_on_One_System

But this doesn't use the "metric" command to put alternate "weights" to each line . . . Not sure if this is the right way or what the difference is. . . .

Oh well - I'll reseach further and hope someone sees this post and can help

 

[rfox]

Anyone?!?

 

[rfox]

Thought I'd try one more time - any tips from the networking experts?!?