If two friends have bad NAT settings (or restrictive firewall/adsl box/network), they will never be able to have a connection between their 1S nodes.
As same, we can also say that we may wait a long time (hours) to be connected if y one of the peers as bad settings.
So, it would be very helpful if the Community Server were able to do (tcp) hole punching for its peers (as it is going to resolve the IP and port modifications for them (CHT)).
Regards