VPN NAT Traversal when both USG are behind CGNAT with unpredictable source port

PeterUK

I'm not sure this will happen due to how it can only be done where by both ends are behind CGNAT with no incoming allowed and unpredictable source port mapping but here is one hell of a way to do it! Not 100% sure it would work.

Here how port 500 Traversal would go then the same for 4500

PeterUK

So after going through how it work it don't then relooked to how might of worked but it ended up being impossible so one end source port must be true on one side

PeterUK

So this is the best that can be done where both end are CGNAT no incoming allowed and one side has source port that are true.