Blog Post

iPhone 3G S: Enable Tethering


So you’ve got a brand new iPhone 3G S and you want to know if you can use the AT&T (s t) tethering workaround everyone’s been talking about? Yes, yes you can. It’s all remarkably easy. It’s almost like Apple (s aapl) wants us to use this workaround — at least that’s the story I’m telling myself.

The good folks over at 9to5 Mac have the step-by-step guide, but essentially all you need to do is run a quick terminal command to turn on the preference in iTunes, download an iPhone carrier update file, restore the iPhone, and as Steve would say, “Boom.” You’re all set to start tethering, just navigate over to Settings ? General ? Network ? Internet Tethering on your iPhone and throw the switch to the “On” position. If your Bluetooth isn’t running at the time, it will generously offer to switch that on for you. At that point, just connect your phone to your laptop through Bluetooth (if you haven’t connected before you will have to pair them) and you’ll be sharing some 3G goodness.


All told, it took about 5 minutes to get it working. I did a quick test checking e-mail, browsing around, etc., and the speed over 3G was pretty good. Right after the connection was established, I did happen to get a nice little welcome SMS from AT&T, but I don’t know if that was coincidence or by design. I’m assuming the message was just the normal welcome everyone gets with a newly activated phone, and that it just happened to be remarkable timing.

It’s unclear what implications the use of tethering in this manner will have for your monthly bill from AT&T, so please use at your own caution. It’s at least nice to know though that I can use it in a pinch if needed. Hopefully AT&T will soon catch up with the rest of the iPhone providers and establish an officially supported way to take advantage of this functionality.

Worth noting is that some users have experienced trouble with their visual voicemail following this procedure. If you do have trouble accessing that feature, simply navigate to Settings ? General ? Network ? Cellular Data Network and within the Visual Voicemail section add “acds.voicemail” into the APN field. Once that is done, you will be able to once again use your visual voicemail.

71 Responses to “iPhone 3G S: Enable Tethering”

  1. Bluebadge

    Ok, so I have a jailbroken 3GS running 3.1 fw. (Pwnage tool used to upgrade) my ECID SHSH is on file with Cydia so I can downgrade to 3.0 if I wish… My question for you boffins out there is this. If I downgrade back to 3.0 will I be able to use the mobile configs settings at Benm’s website to update my carrier settings to enable tethering? As I can’t be arsed waiting to se if a hack for tethering will be available for 3.1fw.


  2. You can easily tether a BlackBerry via Bluetooth with a Macbook Pro i am doing it right now with my Bold. It is the only internet connection i have at home. I can’t justify paying 50 dollars for home internet and the data plan. especially with every store and bar having free WiFi.

  3. I tether my BlackBerry Bold and the Curve i had before, all the time with my Mac and with the PC laptop i had before, i buy movies from iTunes, music and stream Netflix movies and only pay for the regular data plan.

    I have been doing this for almost two years and never have had any issues at all with bills.
    Maybe if people are on a Bittorent site or Limewire downloading gigs of data all the time. But those people are not going to use a phone to do that anyway it would take to long.
    For regular Web surfing and light downloading i seriously about any red flags are going to go up at AT&T.
    Sure they could probably tell you are not just using data on the phone and are tethering, but that is costly to a company to monitor millions of smart phones that have data.

  4. No more tethering on 3GS if you update to 3.1. If you haven’t updated – DO NOT do so. Or else forget about tethering.

    As for WiFi, only if you jailbreak. And if you updated to 3.1, you’re not going to jailbreak for a while.

  5. I have read in several forms that while you are tethering to you lap top using and iPhone and Mac, only apple email and browsing software works. I use Thunderbird and Fire Fox on a Mac Book Pro. Has anybody had any issues with this?

    I can’t use my black berry to tether with my MBP so I am looking into the iphone options.


  6. I spoke with several people using the T-Mobile tether on their Android phones and they all stated that it comes out of their data plan. So, if you have an unlimited data plan … then there is no FEE. This is why I hated Bellsouth/Cingular/AT&T … they nickel and dime their customers to death! Enough already.

    • Mikeyxx

      Yes, absolutely. I use it all the time, but I’m on Rogers (tethering now through Linux). However, I don’t know what AT&T will do. It’s easy but expensive for them to look for tethering. They will be doing stateful packet inspection to see that the information coming from your source (phone) is more than one originating point. The phone when tethered acts as a NAT router basically so when your computer that is tethered asks for a website to be displayed, the phone needs to know if it is its browser looking for the page or is it the tethered computer. It keeps that information in the footer of the outgoing packet. Then when the page is returned, the information is within the header and that is what the stateful packet inspection does, reads all the headers of the packets and make sure there isn’t any nested destinations.

      But it’s expensive to do without slowing down the network, will they do it? Probably, how else will they be able to bill for the service if they don’t know someone is using it or not.

  7. SD_Diver

    Curious – what if I use a iPhone 3.0 user agent in Safari when tethered? Would this make me look more ‘iPhone-like” the AT&T?

  8. Wait a second…arent we paying for unlimited data…who cares if its going through our macbooks??? its viewing the same sh!t on a bigger screen.

    • …actually, no. You are paying for unlimited data TO your iPhone. That’s in the marketing, and in your Terms of Service. AT&T never misrepresented this as unlimited data.

      Otherwise, why not run your whole house’s data needs through your iPhone patched through a good Wi-Fi router? Obviously, AT&T isn’t going to sell you a service plan without limitations.

      That said, go forth with the tethering workaround. Use it when you’re in a pinch for a net connection. You take some risk of a nastygram, or a bill from AT&T, but it seems these are rare, and reserved for people who really push a lot of data.

      An iPhone subscriber earns AT&T about $97 per month in revenues. They would be nuts to kick you off and make an enemy just because you send a hundred MB from your laptop. On the other hand, if you send a few GB from your laptop, they’d be nuts not to call you out.

  9. Andrew

    Brian, THANK YOU SOO MUCH for the info on voice mail setting! Nobody else has that info, and I didn’t know that I have been missing quite a few voice mails since I tethered my iphone.

  10. I’m going to be trying a new service from a company called Zer01
    they say for $80 a month I can have unlimited. voice and data
    and no caps on bandwidth usage, and the tax they claim its 100%

  11. Bryan Schuetz

    I think we’re all right to be cautious, and while I’m encouraged by the fact that when tethered my laptop and phone both seem to report the same IP address (which would I imagine make it more difficult for AT&T to distinguish between them) I’m also fully aware that I’m no expert on network traffic protocols.

    I’m also not a lawyer, but I wouldn’t be surprised if by doing this I wasn’t breaking some clause in some term of service agreement that I signed at some point in the process of setting up the phone.

    All that being said, it’s still a cool workaround and I personally doubt they will come after me if I’m not abusing it. Then again perhaps I’m just being naive, it wouldn’t be the first time.

  12. W.Taylor

    All manufacturers of Internet devices have special MAC Address ranges. No two on the internet are identical.

    With every data packet sent over the Internet, it carries header information that identifies the MAC address of the sending device. I suppose if AT&T wanted, they could ‘sniff’ out the header information and identify which ones are iPhone specific transmissions.


    • John Halbig

      Re: MAC addresses — those can be spoofed easily, and (again) would be moot with the use of a VPN via the iPhone anyway.

      Let’s see what the FCC has to say about exclusivity agreements — once those drop, I’m guessing that the insane charges for tethering, texting, and so forth will start to crumble.

    • MAC addresses don’t go out over the Internet, just on the LAN. However, in the case of AT&T, they may see them since there certainly is some kind of media layer protocol (possibly involving your MAC and/or serial number) between your phone and AT&T’s network.

  13. Howie Isaacks

    I would be very careful with this since AT&T has not officially announced pricing for tethering. I tried this out, and it works great. However, I’m not going to use it until we know how AT&T is going to price the service. I’m sure it will be over priced when they do. The people that I’ve talked to at AT&T say that the pricing will be “competitive”. I wonder how competitive you can be when you’re the only provider of iPhone data service.

  14. They most certainly could detect tethering to some degree, but apparently haven’t tried very hard up to this point. Tethering has been available via jailbreak (and a banned AppStore app) for quite some time, and I haven’t heard of anyone getting slapped with huge data charges.

    As your internet service provider, AT&T knows what protocols are being used, what ports, what you’re connecting to, and even what software you’re using to access the internet in some cases — ever notice that some websites know what browser you’re using? It would be a tipoff to AT&T if all of a sudden they start seeing lots of connections from Firefox 3. The important point is that they have to be looking to notice. My guess is that if they’re going to start investigating, it will be if your data usage goes above the “usual” amount expected for a mobile device. They might also be putting iPhone accounts under more scrutiny now that it’s available without a jailbreak (ie more accessible to the average Joe). No one knows for sure, and they’re lying if they say they do (unless they are AT&T).

    I have a Witopia VPN account I use to maintain privacy when using wireless networks (both on my iPhone and my Mac), which also does a good job of obscuring all network traffic from AT&T’s perspective — they can only tell that my phone is connected to a VPN, a perfectly legitimate use. I’ve always used this when tethering my iPhone in the past, and $40/year is better than $50/month or whatever AT&T plans to charge for tethering. Plus, having a VPN account offers a lot of other privacy benefits.

  15. kshusker

    So does anyone know if there is any way that AT&T can detect this if you use tethering, as long as you don’t go crazy with usage? In other words, if you keep your overall bandwidth use limited, can they tell if you tether?

    • well if you are doing normal surfing…you might be ok. but it can be detected by the users having apps that use none standard ports or if its going through a proxy. it can be detect for sure but if they do anything about it, it might open the doors to a consumers legal action similar to the comcast bit torrent case since i might violate net neutrality.

    • Well, one way they can tell if you tether (if they wanted to) would be to look at your HTTP get/post requests. Each browser has a user agent string that it sends with these that identifies your browser/OS (with varying degrees of reliability). I have no idea if this is how AT&T is identifying people who tether but I’m just pointing out that it’s one of many ways they *might* be doing it.

      You can, of course, “fake” your User Agent to be the same as the iPhone. But, as I said I have no clue if this is the method AT&T is using to track people down and thus can’t tell if that would be effective or not.

    • I just upgraded from a Windows Mobile 6.1 smartphone to an iPhone 3Gs keeping the same AT&T data plan.
      With the Windows Mobile 6.1 I could tether using “Internet Sharing” with Bluetooth connection at no extra cost.
      Does anybody see any reason why I can’t move the SIMM card from my iPhone to my Windows Mobile 6.1 phone when I want to tether?