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How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

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Re: How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

#41

Post by Irfaan »

pieter wrote: post #2

I'd like to see a proper source of this (other than Android Police / iPhone Download Blog). I have used MyWi without having any special settings for tethering (my provider doesn't supply those), and it worked just fine; it would be a bit silly to go through the trouble of setting up a hotspot and making sure you're actively routing the data to the 'wrong' APN. (Note that iPhone Download Blog is the one calling MyWi b…

Just to add another data point - during a recent move, I was temporarily using iPhone + MyWi as my primary internet connection. Nothing particularly egregious - just basic web browsing and SFTP. This lasted for about a week.

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.

Re: How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

#43

Post by Osiris »

kevko wrote: post #16
Osiris wrote: post #5

Does anyone know if tethering can be detected on Android phones? I'm curious what other provides do to try to detect tethering on Android phones.

I wrote a non-root tethering app, so I might have a bit of tunnel vision. 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 li…

Can you avoid these issues by establishing an SSH or VPN tunnel through the 3G/4G connection?

Re: How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

#44

Post by kevko »

Osiris wrote: post #43
kevko wrote: post #16

Earlier quoted context omitted.

I wrote a non-root tethering app, so I might have a bit of tunnel vision. 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 li…

Can you avoid these issues by establishing an SSH or VPN tunnel through the 3G/4G connection?

Yep. Any non-root tethering app should just show the encrypted tunnel as a connection originating from the device itself. Just make sure that DNS requests don't leak when using an SSH tunnel. In fact, a simple port-forwarding app is all that's really necessary for most tunnel cases.

All of this makes a $6-$8/mo SSH/VPN privacy service (e.g., cotse.net) rather intriguing.

Re: How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

#45

Post by zem »

kevko wrote: post #39
zem wrote: post #36

Earlier quoted context omitted.

> First, any good tethering app should be immune to a simple TTL check. If the phone sets its TTL to 255, what can you do?

The goal is not to forward packets blindly like a NAT. You emulate the NAT's behavior by running a TCP state machine in user space and converting packets to regular Android SDK calls. This is what all of the non-root tethering apps likely do, because raw socket access is not allowed.

ooh, i see. nice.

Re: How AT&T Recognizes Unauthorized Tethering from Jailbroken iPhones

#46

Post by rasengan »

kevko wrote: post #44
Osiris wrote: post #43

Earlier quoted context omitted.

Can you avoid these issues by establishing an SSH or VPN tunnel through the 3G/4G connection?

Yep. Any non-root tethering app should just show the encrypted tunnel as a connection originating from the device itself. Just make sure that DNS requests don't leak when using an SSH tunnel. In fact, a simple port-forwarding app is all that's really necessary for most tunnel cases. All of this makes a $6-$8/mo SSH/VPN privacy service (e.g., cotse.net) rather intriguing.

Most properly configured VPN service providers will reroute any DNS request traffic to their private NS servers (e.g., privateinternetaccess.com).

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+)

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