Is there no way around symmetric NAT ruining connectivity in games like SFV?

[banana]

This is more of a rant, but hopefully this also helps people who have run into similar problems to mine.

After a lot of messing around, it seems extremely likely that having symmetric NAT is causing all the "Failed to join battle lounge" problems on my end as well as the very long wait times in ranked matches. Here's an explanation to why symmetric NATs cause problems:

http://www.think-like-a-computer.com/2011/09/19/symmetric-nat/

One important quote is:

"...symmetric NATs are the only types of NAT that cause connection problems with other devices also behind NATs."

Coincidentally, the only people I've been able to play with so far have been behind DMZs, which presumably disables the use of NAT on their end.

Most people would have a modem/router and enable port forwarding to get around this problem, but in my case I don't have one, I connect to the internet through an ethernet port in the wall, which goes to a router handled by my ISP. My ISP seems to handle port forwarding fine for console games like in a Xbox360/PS3, but this is the first time I haven't been able to play, presumably because it's the first time I use my PC for peer-to-peer games like this.

Who is at fault here, exactly? Since SFV and pretty much all fighting games are peer-to-peer by nature (we connect to each other to play), is this limitation with NATs always going to plague these games, or are there solutions that can be implemented within the games themselves?

I can whine to my ISP and see if they can make changes and see if that solves the problem, but this is pretty frustrating nevertheless that this is a problem in the first place. I just want to play games!

[IceBlade]

The linked article explains the reason quite thoroughly, so I'm not going to repeat it in such detail.

As explained, many NAT hole-punching implementations use STUN (or a variation of it). There's a mediation server (master server) which handles & pairs incoming requests through a dynamic port range in order to figure out the public IP address of each end.

In a restricted or full cone NAT, the source ports for both peers are the same, the connection is met at both ends & communication is successful.

In a symmetric NAT, the ports on the symmetric end are randomised and the result will be that it will be listening to a different port than the remote peer, thus never establishing a connection.

From a network engineering perspective, unless all data is routed through a central server that is not behind a NAT - that is, most commercial grade dedicated servers, a symmetric NAT on one end cannot ever negotiate with any other type of NAT without some pre determined port forwarding set in place.

Capcom do not route all data through a dedicated server for each match. In a situation involving active data transfer between only two peers, a direct peer-to-peer connection will always result in the best possible gameplay.

If you can't change the ports your router is forwarding, your only option is to whine to your ISP and either let your connect bypass the symmetric NAT restriction or tell them to open the following ports (There may be more, this is what I saw from TCPView):

20002 (TCP)
30850 (TCP/UDP)
443 (TCP)

[Blackwind]

I've opened these ports and still having issues.

♥♥♥♥♥♥♥♥♥, did you play ESF!?