Pointers on getting Proxmox to play nicely

During this period of social distancing, I thought I would go out to the boat and see if I could create my mobile homelab with minimal components. So, I have my IBM Thinkpad 440T (with 16G, 2 2TB HD, MVIE 64GB boot drive, a Cisco SG300-10, a gl.iNet MT300N portable travel router, a CradlePoint 4G router, and a work laptop.

The first thing I setup was my Cisco SG-300. I defined eight VLANs to provide for the LAN, and one VLAN to provide for WAN connectivity. Since I configured the SG-300 to act as a L3 switch, it was no issue to create a static IP address for each of the VLANs.

Because the particular model of the CradlePoint does not act as a router, I decided to use my $20.00 travel router (which has two ports, one for LAN and the other for WAN) to connect the CradlePoint and the switch. The only goal was to get the PM 6 server up and running, at which point I could remove the MT300 out of the equation since the first image that will be spun up will be pfSense.

I connected the CradlePoint in to the WAN interface and the LAN interface on the MT300 to the switch. Initially, life was groovy! The MT300 had passed an IP address to VLAN 1 on the switch so I thought I could focus on the PM server. After installing PM 6, after rebooting, I noticed that I was not able to connect to the internet. For that matter, unless I connected my work laptop to a default VLAN (VLAN 1) on the switch, I could not get any connectivity on any of the VLAN on the ports.

I looked at the network layout on the MT300, and although there are 2 VLANs defined, I am not able to create any new VLANs (because I think if I were able to create VLANs that mirrored my switch, I think that would fix the problem.).

Right now, I would like to get past this issue and move on to my getting PM 6 running. Should I play around more with getting the MT-300 working (which is running OpenWRT) or should I try to do an emergency router setup on the PM 6 with a bridge and masquerading (pain in the a**).

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Hi kcallis,

Thanks for writing up your mobile homelab set up. It sounds awesome.

So if I understand correctly, this is what we currently have:

4G Modem -> Travel Router -> Cisco Switch -> Thinkpad 440T (Proxmox Server)

And the problem we’re trying to solve is that we don’t have internet connectivity on the Proxmox host?

And ultimately, we want to end up with the following configuration: (?)

4G Modem -> pfSense VM (running as guest VM on Proxmox host) -> Cisco Switch -> Thinkpad 440T (Proxmox Server)

If I have that right, here is what I think is what’s happening:

Traffic coming passed between the travel router and the CIsco switch is actually just untagged traffic which normally defaults to VLAN 1 on CIsco (and most other) switches. (I believe this default untagged traffic is known as the default Native VLAN in Cisco terminology).

As for why you don’t have connectivity on the Proxmox host, here is what I am thinking might be the reason:

If the VLAN subnet assigned to the host’s VLAN is not set up as a static route on the travel router to send it back to the gateway on the Cisco router, it has no idea where to send return traffic to get it back to the Proxmox host. Similar idea to setting up static routing for VLANs on an HP switch here; just in your case replace the idea of the pfSense static routes with your travel router/openWRT..

The fact that you said that you could get connection no problem using VLAN1 on your work laptop connected to the switch but not any of the other VLANs makes me think there’s still a problem in the connection between the travel router and the switch. I think it’s likely to be the lack of the static route outlined above. Running a traceroute to a public WAN address (like from your work laptop on VLAN1 and then comparing it against the same traceroute on VLAN2 might help you out.

I think I would avoid masquerading. It introduces an additional level of complexity we don’t need at this point.