Since I want to use PPPoE, I have set up the first pfSense normally, the second one I have set up to "dial on demand" as well as to an idle timeout of 30s. Also, I disabled "gateway monitoring".

The 2nd box does not start a PPPoE connection on its own. But, if I disconnect the 1st box, it does (like I desired) start and establish a connection on WAN. Unfortunately, once the 1st box comes up again, the 2nd box does not disconnect its PPPoE session and nothing works anymore.

1. Can I somehow investigate why the connection is kept alive? I guess someone/something is using the connection? Or do you know what might keep a connection alive?

2. When the 2nd box is up, I do not have internet access from LAN. It is working from within the box (I can do DNS lookups), but from LAN, neither via CARP IP or 2nd box IP I can ping out or do DNS lookups.

This is a Hyper-V setup, though I think it does not matter. To make CARP work, I had to enable the "allow MAC address spoofing" option on the virtual network adapter, and everything is working fine with the first box, actually I have made the prior box 1 IP the CARP IP and this seems to be working fine for all LAN devices so far.

Thank you all!