How to enable WAN connection to devices on network. Router settings?

[Shifty Geezer]

As an indie dev, I'm wanting to enable WAN access to my network for my own application. The intention is for people to be able to host games on a device (PC or mobile) and other friends can connect via IP address. I've got a friend run it and I can connect on the network to them, but they can't connect to me. I also want to be able to connect local devices over WAN for testing if that's possible.

I'm not great at network stuff! I've looked through and enabled port forwarding etc. A ping to the WAN fails. What are the other options/settings I need to fiddle with on the Sagemcom Fast 5364 that TalkTalk have provided?

Cheers!

[Birchcroft]

In theory all you need to do is:

• setup a Dynamic DNS service so you can access your network from the outside world, using an address such as ShiftyGeezer.hopto.org.
• Assign a static IP address to the device running your application. eg 192.168.1.20
• Setup port forwarding for your app.  So if your app uses port 80 and you wanted to use port 100 on the wan you would setup port forwarding to forward port 100 on the wan to port 80 on 192.168.1.20.

Then you should should be able to access your app from the wan using the address ShiftyGeezer.hopto.org:100

Hope this helps

[Shifty Geezer]

Thanks. Can you please clear up some fundamentals for me?

I was thinking that an IP address is directly addressable from any computer. However, I get the feeling that's not actually the case, and all internet traffic has to go through a DNS server. As such, a home computer cannot just host something as The Internet won't know about it. If so, by using a service like hopto, one informs The Internet that you have a server that people can connect to, making the address usable.

As such, for peer-to-peer games, there has to be a central server that people register their game with so others can find it, because they can't just share their IP address. So for consoles, this is handled by the PSN/Xbox Live backend. Same for Steam.

Therefore, I can use your suggestion to set up my computer for testing and development and people can connect, but for a public game I would have to use a third party service for at least matchmaking.

Correct?

[Birchcroft]

Not quite.  

There are two types of IP address involved here.

• Those internal to your network.  Usually 192.168.xxx.xxx . These are the same for most SoHo networks and are allocated by your router.  Internally you can access these using the IP address. Port forwarding is used to access them from the outside world.
• Your public facing IP address allocated by your ISP, in this case TalkTalk, which will be something like 200.214.6.99.  In theory you can access your network using this IP address.  So instead of the hopto example you would use 200.214.6.99:100 to access your app (assuming port forwarding is set up).  The problem with this is that the IP address assigned to you by the ISP changes from time to time so can not be relied on. 

There are two ways to get around this, and provide a consistent way of accessing your network.

(1) use a DDNS service such as hopto to ensure that DNS servers are updated whenever your public IP address changes so the domain name will always work.

(2) Use a static public facing IP address.  These are generally only available to business customers, although some ISPs will let you have one for and extra fee.  I don't believe TalkTalk offer static IP addresses to their domestic customers, although Plusnet used to at £5 a month.

Large games companies will have bought their own block of public IP addresses for their servers so they have the option of them being addressed by IP address or domain name.  Using domain names has the advantage that you can dynamically redirect it to a different server, eg incase of server failure or maintenance, without the users having to make any changes.  But network and server fail-over policies and techniques are a complex topic beyond simple explanation here.