In Exam 2021, problem 1, part 5, H1 and H5 are according to the solution using the IPv4 address of H6 as destination address in their UDP packets even though it is behind a NAT. How is this possible without for example port forwarding? To me, it would make more sense to assume that port forwarding has been performed at N2 with the tuple (t4, p) that maps to (z6, q) where t4 is N2 IPv4 address and p and q are some ports. What am I missing?
Thanks.
/Joel