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I'm trying to use a VPN to play iPad to iPad Wifi (Local) games over the internet.

Normally you open the game on both iPad's, connect to the same Wifi point and they can "see" and speak to each other.

I figure using a VPN I can put them both on the same network (either both on the VPN or one on the "real" network and one on the VPN).

On my router I've set up PPTP VPN with the ip range 192.168.1.2-50, where the PC's on the real local network are assigned 192.168.1.100+

When I connect one of the iPads to the VPN, using an external WiFi network (BT Openzone) I can ping it as expected (from any machine on the local network). However the iPad's cannot "see" each other and none of the Wifi->Wifi games work.

I've also tried connecting both iPad's to the same VPN, with the result the same. All machines on the local network (and those on the VPN) can ping the iPad's but none of the Wifi to Wifi games work.

I've set both iPads to send all trafic over the VPN and if I check their external IP's they match that of the real network.

Does anyone know how to fix this? And/or what is causing it? Or what further debug information I can provide?

Note: I don't feel this is iPad specific so would prefer if this isn't moved to a Apple SuperUser equivalent


Details on how to enable broadcast over VPN for DD-WRT can be found here http://www.dd-wrt.com/wiki/index.php/PPTP_Server_Configuration#Broadcast_to_VPN_Clients

If you're not using DD-WRT and have a router (not a modem router) then I suggest you look into installing it, if you're a power user, it'll allow you to get much more out of your hardware.

See: http://lifehacker.com/178132/hack-attack-turn-your-60-router-into-a-600-router

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1 Answer 1

up vote 2 down vote accepted

I do not know for sure how the games are communicating with each other (You will need to set up wireshark or something similar to capture the packets to know for sure), but I am willing to bet that the iPad is broadcasting to see what other devices are on the network.

If that is what is happening you need to configure your router so that broadcast packets sent to 192.168.1.255 are forwarded over the VPN link. You will need to check your router firmware's documentation on how to set up routes like that (if it's even is capable).

However if the iPad is doing a Ethernet broadcast instead of a IP broadcast, you are SOL as Ethernet broadcasts do not traverse routers.

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Thanks for the info, will set up some logging to try and figure out what is going on. I imagine broadcasting would be how it's implemented but it's viable it's an ethernet broadcast also, will look into it and report back! –  Pez Cuckow Sep 10 '12 at 11:01
    
On a side note, are you sure that it is using WiFi? The iPad and iPhone both have Bluetooth radios. –  Scott Chamberlain Sep 10 '12 at 12:41
    
Also it could be using a Ad-Hoc WiFi network and not using your Access Point. –  Scott Chamberlain Sep 11 '12 at 21:57
    
It does use Wifi as the options are Wifi or Bluetooth and I can see them both connected to the access point so am pretty sure it's not Ad-Hoc, will try when connected to the same network at different ends of the house (we have 4/5 repeaters) –  Pez Cuckow Sep 12 '12 at 8:53

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