Some AT&T iPhone users, Jailbroken and tethering via MyWi, are getting text messages and e-mails from AT&T that imply they know they are tethering even though they aren't on an official tethering plan. One of our own writers, Andrew was one of those who received the message.
I use MyWi to tether as well but have not received anything yet. (I actually was just tethering today.) I'm not sure how they are detecting MyWi users but I can make some educated guesses.
- Since AT&T offers Personal Hotspot under iOS 4.3, they may have access to data they didn't before, and they're choosing to use it in a pretty crappy way. So if you're on iOS 4.2.1 still (almost all jailbreakers are) and they see you're generating traffic that looks like Personal Hotspot, they know you're doing so without a plan.
- Like Chris says below, browsers use the wap APN. Tethering uses the ISP APN. As such, larger data is expected through ISP not through WAP. So if AT&T sees a lot of WAP data it may raise a flag.
- As several people say in the comments and Twitter, if AT&T sees a TTL reduction that suggests a device like a laptop or iPad in between the connection, it may raise a flag.
- They're just going after heavy data users again and trying to bluff them into switching to a tethering plan and losing their unlimited data. Andrew tethers a heck of a lot more than me. I only consume a fraction of what he does. So that's a viable answer too.
Originally Jailbreakers used MyWi because AT&T took a year longer to offer iPhone tethering than international carriers. Since then they've used it to get around AT&T's ridiculous fees for tethering. (Tethering is free on some international carriers as well.)
Hit the jump to read the e-mail AT&T has been sending out as well as to let us know what you think! Anyone else been getting messages from AT&T? Anyone on iOS 4.3 using official Personal Hotspot? Any PDANet users?
UPDATED: AT&T spokesman Seth Bloom told Phone Scoop:
[ModMyi Forums and Phone Scoop]