"I'm behind a NAT/Firewall" needs updating
First, it points to portforward.com, which we learn from #332 (closed) is now an ad parking lot.
Second, it points to https://support.torproject.org/tbb/tbb-firewall-ports/ which suggests setting FascistFirewall, but that is a client-only setting and relays can't usefully set it.
We should put together some new instructions for relay operators behind firewalls.