Possible ATT crackdown on 3G un-restrictors

[Mr. Chewbacca]

Just a thought, I use MyWi but so little that my unlimited plan still stays under 2gb a month so I think I'm under their radar....... for now. It just occurred to me that they could easily tell that I have a JB phone when I download a big podcast. I think, what is the normal limit? I have been JB for so long I take the convenience for granted. I get that it works by tricking the phone into thinking its on wifi but the network still has record of an over the limit 3g download right?

My assumption is that ATT first flagged the heavy data users then further checked those users for evidence of tethering but I don't have a lot of knowledge about this, would they need to narrow down the pool or could they just as easy check every phone for signs of mis-use. IE over the limit downloads and MyWi. If they could would it be worth it to them to lose the customers that don't overuse the data? Did anyone get the warning email that uses >2gb a month?

Life goes on if I have to add 15.00 to my plan for tethering but it would seriously suck to lose my ability to 3g download. I may use it a few times a year but still...

Thoughts?

 

[ulbador]

Honestly, they probably aren't even using data usage to detect tethering.

The easiest way to detect tethering is to just check the TTL (Time to Live) on the packets coming out of the phone. This TTL value is decremented by 1 as it is routed through a device such as the iPhone. ISPs have been using this method for years to catch people "NATing" traffic with routers when they aren't allowed.

MyWi will probably eventually get around this. With some fancy hacking they can rewrite the packet to increase the TTL value as it is routed, so it looks like the data originated from the device itself.

With the Personal Hotspot, I think it's a little different. With an APN setting, AT&T can actually see the usage straight from the phone. Since 4.2.6 and 4.3, tethering has been its own category on the Usage panel. I think this will be a little harder to get around. While you can easily change the APN setting so it wouldn't report, it would probably take much more indepth hacking to get around the TTL problem as mentioned above.

 

[Mr. Chewbacca]

Thanks! that was the best best explanation I have seen yet! So they most likely already know about the tethering and are just going after the heavy users. Cool for me but kinda sucks for a lot of people

Could any of these tests also tell if a phone is bypassing the 3G download limit? Even if they could tell would it be a breach of contract? I know tethering is specifically forbidden in the contract but are 3g unrestrictors?

I'll have to get out the contract and look it up.

 

[labman]

Wouldn't make more sense to have one thread about tethering then several.

 

[zerostar]

The easiest way to detect tethering is to just check the TTL (Time to Live) on the packets coming out of the phone. This TTL value is decremented by 1 as it is routed through a device such as the iPhone. ISPs have been using this method for years to catch people "NATing" traffic with routers when they aren't allowed.

If I am using my VPN on the iPhone then tethering they wouldn't be able to see any of this then correct?

 

[Mr. Chewbacca]

Wouldn't make more sense to have one thread about tethering then several.

The actual question is about their ability to detect 3g unrestrictors and what response ATT would have, if any.

The fact that they are responding to tethering brings up the question but that's not the subject of the question.

 

[ulbador]

If I am using my VPN on the iPhone then tethering they wouldn't be able to see any of this then correct?

Yep. The VPN happens on a much higher network level than the regular old packets. The TTL decrease would still happen.

 

[8767092]

at&t is likely using two or three database records to attempt to detect tethering. Anyone considering widespread advanced detection methods is simply being unrealistic.

Consider the following:

1) at&t has a database that tracks data usage per line over a long period of time.

2) at&t can use that data to group phone users together. Low, Medium, High, and Abuse.

3) It would costs millions of dollars and tens of thousands of man hours to install, configure, and maintain the network level technology necessary for the advanced detection mentioned in previous posts.

4) By finding the average use per group per time of month, at&t can make an educated guess about users that are tethering.

5) Toothless letters are sent out to potential abusers which will cause a certain portion to stop.

What data are they interested in?

The total amount of bandwidth used per month, per day, and per hour.
The plan you are using. Unlimited users are the targets.
Unusual spikes in data usage when traveling or other unusually high data usage that breaks from the base line established from historic data usage.

 

[dhlizard]

I'm sure it's based on more than an educated guess...

AT&T tethering letter

 

[ulbador]

The total amount of bandwidth used per month, per day, and per hour.
The plan you are using. Unlimited users are the targets.
Unusual spikes in data usage when traveling or other unusually high data usage that breaks from the base line established from historic data usage.

You could do all this. Or you could just use the VERY well established data available to an ISP as the "man in the middle"

 

[byeehaaw]

from what im reading, theres no difference in att catching ya if you are on 4.2 or 4.3? they can tell either way?

 

[i hate phones]

The actual question is about their ability to detect 3g unrestrictors and what response ATT would have, if any.

The fact that they are responding to tethering brings up the question but that's not the subject of the question.

i could be wrong, but isn't it apple that made the phone to restrict large downloads and not ATT? if that's the case, 3g unrestrictors bypass limitations of the phone not the carrier, so that shouldn't be a problem.

 

[thep33t]

at&t is likely using two or three database records to attempt to detect tethering. Anyone considering widespread advanced detection methods is simply being unrealistic.

Consider the following:

1) at&t has a database that tracks data usage per line over a long period of time.

2) at&t can use that data to group phone users together. Low, Medium, High, and Abuse.

3) It would costs millions of dollars and tens of thousands of man hours to install, configure, and maintain the network level technology necessary for the advanced detection mentioned in previous posts.

4) By finding the average use per group per time of month, at&t can make an educated guess about users that are tethering.

5) Toothless letters are sent out to potential abusers which will cause a certain portion to stop.

What data are they interested in?

The total amount of bandwidth used per month, per day, and per hour.
The plan you are using. Unlimited users are the targets.
Unusual spikes in data usage when traveling or other unusually high data usage that breaks from the base line established from historic data usage.

you must work very slow and charge a ton per hour. The tech is out there for this type of detection, ust needs to be modified and tweaked to work in ATT's case. No need to reinvent the wheel.

 

[Mr. Chewbacca]

i could be wrong, but isn't it apple that made the phone to restrict large downloads and not ATT? if that's the case, 3g unrestrictors bypass limitations of the phone not the carrier, so that shouldn't be a problem.

Hadnt thought of that, it would be a good idea for Apple to do it. I know to many people that dont know the first thing about their phone and would try to download a full movie from itunes and expect it to take a minute.

Maybe it is just Apple. I wish they would allow a way for users to turn off the restriction with out jailbreaking.

 

[Cortezbanks]

Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

Since we are not AT&T I don't think we know the answer to any of those questions

 

[Mr. Chewbacca]

Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

Since we are not AT&T I don't think we know the answer to any of those questions

Hense the name Mac Rumors

 

[jav6454]

Well 3G Unrestrictor will basically allow all downloads to happen to your iPhone. So yes, AT&T might confuse you for tethering. That said, there is no way they can physically crackdown on 3G Unrestrictor users. The TCP/IP packets are signed by the iPhone as coming from it. Using 3G Unrestrictor would just eliminate the limit Apple said. There is no network tell-tale sign to show.