Tag Archives: wifi

PPTP over cellular network with iPhone 3GS

ever since I upgraded my iPhone to OS3.0, I’ve been having trouble trying to get PPTP VPN to work. Never had the time to seriously look at it until now.

My VPN end point is a Linksys WRT54GL running with DD-WRT. I know that PPTP service works there as I can connect with my notebook, even with my 3G dongle.

Initial findings pointed towards the support for encryption on the DD-WRT implementation, and it has to be forced to “none” on the iPhone. Even that didn’t work.

With the release of OS 3.1, I started to tether my notebook to the iPhone, and through that, the PPTP will fail. That stumped me! Initially I thought could be due to the NAT implementation to enable tethering.

With trial and errors, I found out that over a WIFI connection, PPTP connection will work. Did I forget to mention that CISCO based IPSEC VPN to my office network works nicely over cellular and WIFI? That really baffled me. So, there’s something that’s in place that only works for IPSEC over cellular.

Finally, I came across some forum postings that lead me to the solution. There are many other people with similar issues in Canada and USA, and for some, they are able to tweak their APN on the phone to a different one and it worked for them. Of course they needed to be on different data subscription etc… for that to work.

I’m in Singapore, and my cellular provider is SingTel. I whipped out my iPhone 3GS and compared it’s APN settings to my 3G dongle for my notebook. Wallah! they are different, even though they are both with SingTel. I swapped in the new APN settings on to the iPhone, and PPTP started to work.

So, for all those in Singapore and on SingTel with similar needs and issues, the solution is to change the APN from “e-ideas” to “internet”. And here’s SingTel’s official instructions. BTW, these instructions are generic for all data devices.

For everyone else, what I realize from this is that some services/ports are controlled by the service provider. So, just by changing the APN won’t work if you don’t have access to the relevant APN.

If you need some guide on how to set your APN on your iPhone, the official Apple guide is found here.

*update 2009 Oct 09* after changing the APN, the “tethering” feature disappears. But if I reset the “Cellular Network” settings, “tethering” comes back. Got to figure out how to enable both.

Best Home Router?

For a techie like myself, I tend to prefer devices which are less of an all-in-one design. These devices though reduces the clutter you may have, but makes the situation more restrictive when you want or need an upgrade. You’ll end up having to either find a new device which has all the functions, or you’ll need to start to break them up.

This is especially true for my home broadband connection. I don’t like to use an all-in-one modem/router/wifi device. Although I don’t have a choice to use one provided by my ISP,  as I need it for the VOIP function it provides, but I still use another router to perform the routing function.

So, I have a 2wire 2700HGV-2, it’s a VOIP/WIFI/DSL Modem/Router rolled into one. I only use it for the VOIP and DSS Modem function. For Router, I use a Linksys WRT54GL (with a 3rd party firmware hack).

Don’t trust my 2700HGV-2 to do everything, as it ends up hanging every other day. With this combination, my overall setup runs more stable. And on top of that, I have a great router that does a lot more.

How about giving you a day by day chart on your internet usage volume, a realtime chart on your network & internet traffic, or the ability to create more SSID for your home WIFI network, for those times when a friend visits, needs to have internet access on his iPhone, but you want to only grant him “guest” access? These are features of commercial routers which are at the cheapest, several hundred dollars.

The Linksys WRT54GL costs under S$88 and DD-WRT (the 3rd party firmware) is free! [donation to the developer is available if you like the firmware]

You just need to download and re-flash the firmware and you’ve upgraded your S$88 router to be capable of features found in a US$399 router!

I’ve been using DD-WRT for a few years now, and I totally like the stability and what it can do for me. In fact, one of my main reasons that I encourage my friends to use it is to setup bridged wireless networks.

My next upgrade to my router will definitely a router capable of running DD-WRT, and provides good wireless N performance.