OPNsense VM & Virgin Hub 4

[brianjg]

I'm trying to get my OPNsense setup working and hitting an issue with the DHCP assignment to the WAN. I've searched through a bunch of similar posts but most have no outcome or solution.

My network layout is below:

hub4 -> netgear g324 switch -> esxi host (uplink) -> OPNsense VM.

I've a vlan assigned to the port that the hub4 connects to which isolates traffic to just the OPNsense VM.

I'm able to place the hub4 into modem mode and this appears to be successful. Initially the OPNsense VM receives a DHCP IP in the 192.168.100.x range which matches the range that the hub4 is in when operating in modem mode.

This should then change to a public IP from Virgin but this process doesn't complete (this is what happens if I connect a windows VM to the same uplink instead of the OPNsense VM).

I'd rather avoid building a physical box for this so if anyone has similar experience or managed to get it working, I'd love to hear from you.

[Splodge]

Not with VM anymore, but I had something similar.

Im on PPPoE now so can't check directly, but I think I used the option "reject leases from" to refuse DHCP leases on your WAN interface from 192.168.100.1, so once VM Hub had negotiated real internet address for modem mode, OPNsense WAN would only get the real internet address...

As an aside, I used to virtualise, but have now moved to physical - having internet down whilst trying to update or fix ESXi became tiring real quick, especially with the family breathing down neck why they couldn't get online!

[Splodge]

Just to follow up; I’ve found my old notes on this with my hub3.

What happens is that the VM hub drops layer1 connectivity (ie physical) when it switches from an internal DHCP to internet DHCP. This drop in connectivity triggers the endpoint to renegotiate a DHCP lease so the address changes from the 192.168.1.1 to your public IP.
As you have intermediate infrastructure (switch and ESXi vswitch) that won’t propagate this down/up behaviour, nothing is triggering opnsense to renegotiate a DHCP lease, so it remains on the 192.168 address until the lease expires.

So the fix I stated originally should work - as you refuse the lease from 192.168.100.1, opnsense will keep retrying for a DHCP lease and eventually get one in the public internet range once the cable modem fully initialises…

[brianjg]

That was really helpful and allowed me to find a similar post https://forum.opnsense.org/index.php?topic=26468.msg127815#msg127815

Blocking the dhcp and modifying the DHCP config allowed the WAN link to come up.

Thanks again.