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I have no problems connecting to my office's VPN (PPTP) using 3G on my iPhone. I am also able to connect from computers on my home network over ethernet or WiFi (Netgear RangeMax WPN824v3 router).

However, my iPhone will not connect when it is on WiFi. It says "Connecting...", then "Starting...", where it hangs for 30 seconds or so before displaying the following message:

"A connection could not be established to the PPP server. Try reconnecting. If the problem continues, verify your settings and contact your Administrator."

Router firmware is up to date (according to the router), and regular internet services work just fine on my iPhone when WiFi is enabled. Does anyone have any troubleshooting advice?

asked 08/11/2011 10:29

AngryBinary's gravatar image

AngryBinary ♦♦


9 Answers:

Is your home the same subnet as the office?

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answered

aarontomosky's gravatar image

aarontomosky

Yes, if I understand correctly, when my home computer is connected to the VPN, it uses the same subnet mask as the computers at the office. Same goes for my phone on 3G.
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answered 2011-08-11 at 18:32:56

AngryBinary's gravatar image

AngryBinary

That causes problems like ip conflicts and other bad stuff. Change your home ip range and I bet it works. So if you were 192.168.0.x try 192.168.15.x
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answered 2011-08-12 at 15:11:31

aarontomosky's gravatar image

aarontomosky

I misunderstood the question. No, my home network uses a different subnet, so the issue is not IP conflicts. IE, home network IPs are 192.168.1.*, while VPN IPs are 192.168.2.*. As I said, other computers on my home network can use the VPN, just not my iPhone.
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answered 2011-08-12 at 15:29:18

AngryBinary's gravatar image

AngryBinary

Are the home computers wired? Is there something in your router that makes wifi more restricted? What type of router/access point is it?
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answered 2011-08-12 at 16:11:54

aarontomosky's gravatar image

aarontomosky

sounds like you have trouble accessing a local VPN server via an external address while being on internal network.
take a look at your office's router configuration. look for an option called either "Filter Internet NAT Redirection" or "NAT loopback".
what is the model of your office router? not all routers support NAT loopback - in this case you have to access the local server by the local address. take a look here for a general explanation:
http://www.dyndns.com/support/kb/loopback_connections.html
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answered 2011-08-12 at 16:29:14

maximus5328's gravatar image

maximus5328

Home computers are both wired and on WiFi (there are several). Connections to the office VPN work in both wired and unwired connections. Se OP for router type.

I would rule out issues with the office's VPN, unless unsupported NAT loopback explains why specifically only my iPhone cannot establish a connection with the VPN via the Internet gateway on my home network, while other machines using the same Internet connection can. I will look into that info and try to get those router specs next week.

Just to clarify the success/failure conditions:

Computers connected to home network via ethernet or wifi CAN connect to office VPN
iPhone connected to home network via wifi CANNOT connect to office VPN.
iPhone connected to Internet via 3G CAN connect to office VPN.

I'm going to try using a different router at home to see if that has any effect. If it does, I'll provide an update.
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answered 2011-08-12 at 21:11:18

AngryBinary's gravatar image

AngryBinary

So, I have another wireless router on which I've installed DD-WRT firmware. I made this my gateway router, and now my iPhone VPN works.

The wireless signal with the DDWRT router isn't as good as with the Netgear, so I kept that on as an additional access point, and everything is working just fine now.

Plus, I really like the DD-WRT administration panel a lot more than Netgear's. However, I'd still like to figure out why the RangeMax router was breaking the iPhone VPN. Here's the weird part - even if my iPhone is connected to the Netgear access point, VPN works as long as the DD-WRT router is my gateway. If I make the Negear router my gateway, then VPN fails. I would suspect that it's a lack of protocol support, but then wouldn't I have seen VPN failing for the computers on my network?
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answered 2011-08-13 at 14:03:36

AngryBinary's gravatar image

AngryBinary

No answer on why protocol support differs over WiFi as opposed to wired, but at least I was able to narrow the issue down to the router. No other answers really addressed the problem, but I don't think all participants understood that the VPN server was not on the LAN I am connected to.

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answered 2011-08-13 at 15:48:56

AngryBinary's gravatar image

AngryBinary

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Asked: 08/11/2011 10:29

Seen: 164 times

Last updated: 11/27/2011 05:18