I have configured my residential ISP’s modem to run in bridge mode, where NAT and any other firewall or other services are entirely disabled in the modem. However, succeeding my doing this I realized that if I pluged three computers into the back of the modem (in bridge mode), each laptop or server got a public facing IP address! I tried 3 at once, but did not try for more.
That said, despite these IP address being ostensibly dynamic, I do seem to be able to get a few of them. Being as this is the case (they are not sequential in assignment) can I use this capability to setup CARP?
It is worthy of nation that when I plugged in a Linux box I had, I was able to SSH into it from the public internet (in the same manner I ssh into my pfSense box with a different public facing IP address my ISP assigns to it when it DHCPs its WAN address from the DSL modem in bridge mode).
If my modem were offline for more than 24 hours or there was a regional network outage I am sure my IP addresses would change. Although, my IP address is used with DDNS so I can obtain it remotely and log back in remotely.
Incidentally, my DSL modem is on its own VLAN with the WAN port of my pfSense box. So there is no reason to think that I could not have more pfSense boxes on the same VLAN that would get a public IP address via that VLAN from the DSL modem. No other hardware is connected or using that VLAN except pfSense (I have another VLAN for local LAN traffic). The pfSense box I built originally is using VLANs as it has only one ethernet port on it currently (thus it routes between VLANs), though I have a second port to add once I test it.
Any ideas on if this is usable to setup CARP?