How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones
iphonedownloadblog.com
iphonedownloadblog.com
There are more knowledgeable people than you working on the issue. That said, I haven't gotten an evil text from using PDAnet, yet. Then again, I don't tether that much and when I do it's not a lot of data.
Of course that wouldn't stop AT&T & Co sniffing browser strings of high data users, but that's a more complicated system to implement.
(Note that iPhone Download Blog is the one calling MyWi by name)
Also, if this is the case, wouldn't it be easier for AT&T to just disable the tethering APN for you if you don't have the tethering option? That would seem to be much more effective.
Seriously, wouldn't it always have been easier just to cut customers off to prevent things like astronomical texting overages? That would interfere with that beautiful revenue stream.
That was at least 1 billing cycle ago, and I've yet to hear a peep from AT&T. My suspicion is AT&T is (currently) just looking for users with excessive data usage.
In the same vein, has there ever been a verdict on the legality of unofficial (MyWi-like) tethering?
To start with, tethering without paying for it is definitely a contract violation, and AT&T could cut off your service, retroactively charge you for it, or do whatever else (within reason) the contract provides for. There is little or no legal ambiguity about this. You are getting a service for free from AT&T that other people are charged for, so you're breaking your deal with them and owe them damages.
The (slightly) more interesting legal question might be whether AT&T could ask a prosecutor to bring criminal charges. My uninformed guess is they could, based on something like "theft of services." If I charged $20 a month for you to come fill up a one-gallon bucket any time you wanted from my well, and instead of a bucket you filled up a tanker truck, it would be theft plain and simple, because you'd knowingly be taking something from me without my permission.
(Actually I hate physical metaphors for computer stuff, because they usually distract more than help if you're talking with reasonably technical people. So let's not get sidetracked with questions like, "what if I filled up the tanker truck _with the bucket?_" [Unless you happen to enjoy pointless arguments as much as I do, in which case go for it.] The point is that the contract permits you to access AT&T's network in certain ways for a certain price, and you're accessing it in different ways without paying the different price, and the law's not too likely to be on your side for that one.)
This is all probably hypothetical, though. AT&T wouldn't bother to bring an expensive lawsuit or risk negative publicity from criminal charges, when they can (perfectly legitimately) charge you extra under the terms of your contract and dare you to fight it.
IAAL, in case that changes your assessment of a random person's opinions on the internet.
Here's a metaphor: Imagine if the water company charged you per gallon for water you used, but then added an additional charge for having a shower. Since you own plumbing fixtures to which the shower connects, and pay for every gallon, we would consider it unfair for the water company to charge extra for an "authorized" shower.
As far as theft of service, what on earth have you stolen? You pay for the data you transfer. Tethering is simply an "unauthorized" (by the vendor) use of that data.
The real problem is that somehow the wireless companies, unlike residential ISPs, have gotten away with not being labeled as pure data transfer companies. It should be none of their business what data you send, but unfortunately that's not (legally) the case.
If they were regulated like a utility (water or electricity, for instance), you would see any and all arbitrary surcharges disappear, and these happen to be the biggest cash cows for these companies.
Wait, does anyone charge a per-kilobyte data charge? I thought most plans either had unlimited data or some large cap.
What I don't understand is how they decide how much to charge for tethering, especially for the capped data plans. Presumably, whether you download 2GB of data straight to your phone vs. 2GB of data through your phone to your laptop doesn't affect their ability to provide network service, so why should they care? In that case, they're simply charging more because some people will pay it. I understand that, but it still rubs me the wrong way.
Its a case of "wait! I didn't really mean all". Its the classic fat man at the buffet problem.
What they sold you is in the contract, which specifies non-tethered data access. To continue your water analogy, they sold you all the water you could carry in that bucket, and you signed a contract saying you wouldn't try to connect the bucket to anything else.
This is really straightforward contract law. If you want to do something, don't sign a contract promising you won't do it.
Unless we get strong wireless net neutrality.
the tethering plan is a facilitator fee since greedy apple agree to limit features.
it's just like buying an app instead of writing your own.
if you can get your own way of using data you pay for, good for you.
now, forcing you to pay a facilitation fee for something you already have, seems a little mob like.
And the exemption only applies if "circumvention is accomplished for the sole purpose of enabling interoperability of such [software] applications, when they have been lawfully obtained..." One could argue that skirting carrier rules on tethering is different from enabling interoperability.
Further, it has no bearing on any contract you may have with your carrier.
I'm not sure how moot. A few iPhone jailbreaks have exploited vulnerabilities that would allow an attacker to execute arbitrary code on a user's device. So, while pretty handy for delivering a jailbreak payload, equally devastating were someone to decide they wanted to pilfer some address book content or damage system files.
I'd say patching such vulnerabilities is important, though the short-term jailbreak opportunities are nice. Apple also verifies a checksum of your OS installation to prevent you rolling back to old, vulnerable OS versions. So, legal or not, Apple isn't taking a nap on jailbreaking.
First, any good tethering app should be immune to a simple TTL check. The most likely culprits are instead application traffic patterns. The following immediately come to mind:
- Browser user agents
- Automatic status checks under both OS X and Windows
- Application behavior:
* Netflix and Hulu on Android isn't supposed to happen.
* Browsers like Chrome are very aggressive and can open dozens of simultaneous TCP connections. DNS prefetching can also generate dozens of requests over UDP in a very short time window.
All of this makes a $6-$8/mo SSH/VPN privacy service (e.g., cotse.net) rather intriguing.
Another thing I'd like to mention is MPPE is not functioning in most Android builds, so don't rely on PPTP based VPNs on your phone - encryption won't work! Make sure your VPN service provider has IPSec/L2TP tunneling available.
Obviously root users should opt for OpenVPN. (e.g., cyanogenmod 7+)
If the phone sets its TTL to 255, what can you do?
My Droid X has an odd property such that connecting it via USB (in USB mass storage mode) causes BSoD, so I've been looking for a way to transfer data without a connection.
The most promising was to run an FTP server on the phone (through a high port, since the lower ones like 21 are protected). This works for me intermittently, and is super-fast when it does, but more often than not, I'm told that it can't connect. The exact same behavior occurs with several different FTP server apps, as well as an HTTP server. It's not due to DHCP shuffling my IP address, and it may even work briefly for a minute before the connection breaks and can't be re-established.
On the other hand, going in the other direction works OK, either through FTP or through an SMB share to my desktop. Unfortunately, this method is painfully slow (I don't know why).
My solution, then, is to do any transfer via my notebook computer, to which the phone can connect via USB with no trouble.
Anyway, the only explanation I can think of for the mostly-not-working FTP server is that there is a watchdog that's looking for the phone to act as a server, and when it detects a port sitting there, it closes it. That's just my theory, but I can't think of anything else to explain the behavior.
I say this because I've noticed what seems to be similar behaviour with servers running on my hacked kindle3 (wifi only). They stop responding until you generate traffic from the kindle, which kicks the wifi card up from some sort of lower power level, or something.