To quote myself from my post in the "technical" forum:
quoting myself from post #30 in the stickied thread:
@ EVERYONE - IMPORTANT
I have seen that message from IronClad "...Most people will not be able to join your game...." everytime I've hosted since the first 2 or three games I hosted (and I haven't changed anything on my end). The games I host are still able to be joined by EVERYONE and everything works like a charm! What this means is, that IronClad have intruduced a "connection checking" method on their end which takes into consideration WAN ping, IDENT (maybe), open ports, etc. If you fail even one of those, their message pops up. While ping and ident are an easy way to see if a host is online or not, they're not required at all for the actual "connection process".
To re-cap, seeing that message from IronClad doesn't at all mean that it won't work. Ever since they setup their "connection-testing" I've been getting that message as well. I don't allow WAN ping or IDENT so I'm assuming that's why my setup "fails". In any case, I am able (and have many times now) to HOST without any issues whatsoever!
there ya are..