Hi!
In german boards there are several speculations about how the N1's WiFi tethering works and how carriers might detect it. But there are no real facts, it seems like there is no one, who really knows about it.
Maybe here are some kind of "cracks", who really know what they are talking about and can provide some real information about it.
How does N1-tethering work? I guess it uses NAT-routing. Is this right? And the probably most important part: How do carriers detect tethering? They officially claim, they could detect it. But the question is, which way do they do this? Can they only detect if you use tethering at all, or do they also have the ability to separate between tethered data and phone's data? Only in that case they would be capable to bill the tethered data (here in Germany some carriers do not prohibit tethering, they can only charge about 50 cent per MB).
Is it possible, that the carrier only detect several devices, that connect to the internet using tethering? I'm a vodafone-customer and I've tried tethering my iPad and my Linux-Netbook several times. Nothing has been charged. Other customers, having the same data-plan, reported, that they habe been charged for tethering within minutes.
Maybe someone can answer my questions.
I dont know how it works but "I would imagine the request headers are what the provider is reading in order to determine the device/browser that is making the request."
http://talk.maemo.org/archive/index.php/t-3757.html
If it really is like that, then I would just have to use Cisco-VPN on my iPad and they would not be able to read any requests anymore.
But someone in the official German vodafone-board said, the user-agent doesn't matter. And he seemed to be very sure about that. But unfortunately he didn't tell anything else. If you think of Dolphin for Android, which allows you to change the browser-identification, it really looks like this is nothing the carrier could make use of.
cymru said:
I dont know how it works but "I would imagine the request headers are what the provider is reading in order to determine the device/browser that is making the request."
http://talk.maemo.org/archive/index.php/t-3757.html
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I don't believe this to be accurate as phones are capable of changing their user agent to mimic a desktop browser, so it wouldn't be a reliable way of identifying a tethered connection.
IMO, there is no 100% fool proof way as it sits. The carrier can look at the traffic patterns though and might be able to figure it out though. Remember when you're connected to your carrier everything you do is going through their gateway, so they can see everything you're doing.
I agree that if you're wanting to make 100% sure they don't know, a VPN tunneling traffic would work. Once the traffic is encrypted, they have no way to tell what is happening, aside from the actual amount of data being transferred, which is why a lot of carriers in the USA or switching away from unlimited data plans and offering only limited ones (i.e. a 2gb or 5gb limit on plans).
It was discussed here a couple of months ago, I remember..
The discussion ended in - if the phone specifically didn't send the carrier any sign that it's tethering, detection of tethering would require heuristic scan patterns on the data that's being transferred - and would violate some "internet openness" rules in the process, and possibly allow a legal case against the carrier.
So, do you by any chance have custom ROM and your friends have official carrier ROMs? That might explain the difference.
People in spain have reported being charged more by vodafone (they charge you more if you tether and your plan doesnt cover it) by simply using an app on the phone that changed the browser's user agent to mimic a desktop one.
I dont know whether it is or it isnt legal to read the 'headers' of HTTP messages. It's more to do with the protocol than with the content, and both ends need to be able to read these things to actually work, some routers may even scoop just to adjust to different QoS patterns or whatever. So it might be legal after all.
Port activity can tell you're tethering or not; moreover, tethering does likely bypass proxy server which is used for phone only.
Ok, to find out more I've made a little research about how to generally detect Network Address Translation and I've made some tests.
As it seems, the Browser-Identification won't work. Maybe in spain there are some data-plans which only allow browsing with the special phone's browser and only using HTTP-Connections. But that's not suitable for a real data plan, which allows you, to send every data you like from your phone. On the other hand, at least in Germany, I think they wouldn't be allowed to read the data content of TCP-packets.
Then I've used a packet sniffer to find out, how different devices (N1, iPad and Kubuntu10.04) handle things like outgoing ports and packet IDs.
Both won't be very likely to use by the carrier, because Android doesn't increment them, but uses it by shuffle. The iPad also shuffles the packet IDs, but increments the ports. I think this will not matter, because the NAT will redirect the ports anyway. Only Kubuntu increments packet IDs and as they normally aren't changed by NAT, carriers could detect that. In general, all of the devices used outgoing ports between 35,000 and 55,000.
Possibly they could look at the time to live of the packets. The interesting question is, how the N1's NAT handels the TTL. Normally, a router decrements the TTL by 1. But it doesn't have to.
All of my tested devices use a TTL of 64 for outgoing packets (no one will wonder about that, because all those system are based on UNIX or Linux). So, if the NAT decrements the TTL, the carrier could detect tethered packets quite easily. Normal packets would reach the carrier's gateway with TTL 64, tethered packets with TTL 63. Maybe, the NAT doesn't decrement the TTL. Then the carrier wouldn't be able to detect it this way, except of this: As I read, Windows-Systems use a TTL of 128, so the carrier ould detect this immediately, no matter if it's decremented or not. This would explain why some people tell they could tether other phones without being billed, but getting charged when tethering their PC. This could only be covered, if the NAT would rewrite the TTL with 64. It don't think it does.
Maybe someone, who has a rooted phone (mine is not rooted, it's a normal FRF91), could install packet sniffer from the market and then catch some packets while tethering. Then we could have a look at the packet's headers and maybe find out, what the NAT does with the TTL.
FYI this isn't technically a problem in the US - it's illegal for carriers to monitor the actual data streams without a warrant.
My understanding is that tethering (WiFi/USB) can be accomplished in two different fashions.
1) The phone (in this case the Nexus One) acts as the modem and router and re-requests whatever the tethered device requested. Thus, the mobile operator sees the Nexus One as using the DATA rather than the actual device requesting the DATA.
2) The phone simply passes the requests to mobile operator along with some identifying info about the requesting device. (the preferred method by the mobile operators)
I have no idea which method the Nexus One (FroYo) employs, but I have a suspicion that it is method 1.
Dan
i Will say it does work as a wifi hotspot, so i connected using my ipad up to the ssid the nexus made, and connected fine, but un sure if charges will appear, i will keep a eye out on my next bill.. but they dont detect then that saves me $25/mon for the 3g data, if i can just use my phone $30 unlimited..
I was wondering about this as well. I have the current $25/mo 2gb plan and I sometimes need to use my laptop to check things that I need a larger screen for (Mostly graphic design attachments like illustrator and photoshop files). Would AT&T detect my using the Nexus One as a hotspot, and if so, would they charge?
I think the whole tethering thing is kind of ridiculous on AT&T. You're paying an extra $20+ per month to use the data you're already paying for except on your computer. They've been dealing with Apple for far too long...
In UK 3 know I'm tethering...
On using my Laptop tethered I get a 3 splash screen on first opening up a browser (IE or Firefox). There don't seem to be any other issues (everything else then works fine & dandy) ... yet...
Can't be that long before some carrier decides to clamp down on tethering some more...
Lodger
theartfullodger said:
In UK 3 know I'm tethering...
On using my Laptop tethered I get a 3 splash screen on first opening up a browser (IE or Firefox). There don't seem to be any other issues (everything else then works fine & dandy) ... yet...
Can't be that long before some carrier decides to clamp down on tethering some more...
Lodger
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Nexus bought from their network? Rooted? What ROM?
The only viable (and probably legal) way for an operator to detech tethering is via looking data consumptions, other methods discussed over here although technically possible, would be administratively expensive even if legally allowed... I suggest if you are on an unlimited data plan and want to be heavy on tethering do it from the start not later on in order not to raise any flags on the operator side.
Cheers, sub
Sent from my Nexus One using XDA App
unknownrebelx said:
I was wondering about this as well. I have the current $25/mo 2gb plan and I sometimes need to use my laptop to check things that I need a larger screen for (Mostly graphic design attachments like illustrator and photoshop files). Would AT&T detect my using the Nexus One as a hotspot, and if so, would they charge?
I think the whole tethering thing is kind of ridiculous on AT&T. You're paying an extra $20+ per month to use the data you're already paying for except on your computer. They've been dealing with Apple for far too long...
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Click to collapse
I've been using my N1 on AT&T to tether a pretty good amount and had no complaints. I even stream netflix movies and haven't heard a word.
obviously our phones send and receive data over wifi. when tethering, the phone is still sending and receiving data over wifi, it's just connecting to another device. not to be rude but it is a pretty easy concept. it is an amazing thing though.
right now i am on a camping trip, and i of course brought my phone and laptop with me so i have been tethering a bit. i just happened to be in an area with fantastic signal strength and speedtest.net shows that i am getting up to 2.5Mbps down, and about 1Mbps or so up. it's working GREAT! it's still not cable or fios fast, but it's fast.
Tethering on Talkmobile
I've recently get an unlimited data Talkmobile contract (UK) and I'm thinking of tethering (it's against T&Cs). Has anyone else done this? If they don't detect it, it's a great deal at only £12 month (though the unlimited deal which I have got is no longer available).
I was thinking, the mentioned methods of detecting tethering, even if they are viable and legal, might not be enough for the operators to prove that I was tethering, and hence they couldn't legally do anything about it. I don't know if this is the case or not (but I think I'll choose to believe that).
If I can tether, it means I can buy the PS Vita WiFi only and have as much connectivity as the 3G version!
Sounds like a good project for this weekend. I'll do some packet sniffing and post if I find anything. TMO in US, though.
would the carrier (Three in the uk) be able to detect tethering if i connected my phone to a vpn. because then surely all data would look identical?
HTC Desire, cm7.1
Having spent many hours trying to resolve this with Virgin Mobile (supplier) and Samsung UK (neither of which had a clue) on the Phandroid forum I've finally found a fix that works . If I could find my way back to the post I would give full credit here, but I can't until find it again.
The problem is with WPS. I opened the WPS settings and on the (Belkin N+) Router main menu followed: Wireless - WiFi Protected Setup & found it 'Enabled'.
On the phone I went to Settings - WiFi and on the 'WiFi Networks' page selected hard menu key which gives the option 'WPS PIN Entry' and provides a PIN number to put into the router. Once I'd done this the phone connected immediately.
Once I'd done a bit of Googling I couldn't see any good reason to have WPS enabled, I've even found on line several posts that say it's a security liability when enabled, so I've switched mine off. It seems to have made no difference whatsoever to my other laptops, phones etc.
Perhaps someone on here could indicate to me if, why and what issues I may have set in motion by switching it off.
I hope the fix works for you!
Wi-Fi Protected Setup (WPS; originally Wi-Fi Simple Config) is a computing standard that attempts to allow easy establishment of a secure wireless home network.
Created by the Wi-Fi Alliance and introduced in 2006, the goal of the protocol is to allow home users who know little of wireless security and may be intimidated by the available security options to set up Wi-Fi Protected Access, as well as making it easy to add new devices to an existing network without entering long passphrases.
Prior to the standard, several competing solutions were developed by different vendors to address the same need.
WPS has been shown to easily fall to brute-force attacks.
It seems WPS has been cracked (design flaw - it accepts repeat PIN attempts, and lets you know when you've got the first 4 right).
I'm no expert by the way - just got this from browsing (also found a download link for the hacking software very easily!).
A major security flaw was revealed in December 2011 that affects wireless routers with the WPS feature, which most recent models have enabled by default.
The flaw allows a remote attacker to recover the WPS PIN in a few hours and, with it, the network's WPA/WPA2 pre-shared key.
Users have been urged to turn off the WPS feature, although this may not be possible on some router models.
Thanks Raistlin - I'd seen something similar about the security issues. I don't understand why it is that, with WPS enabled by default for years, this is the first bit of kit that's had a problem connecting to it. It's bizarre and only compounded by the lack of knowledge of the problem by any of the agencies involved in providing the phone - Samsung, Google Android or Virgin Mobile. It's very, very annoying.
Gents,
I have been using my Nokia 8 (T-Mobile service) wiFi tether to connect to a game on Fantasy Grounds for some time, but just recently have lost ability to do so. (Despite the fact that I can do all other things internet while tethering to my Nokia 8)
This was around the time I installed the February security patch, but I'm not 100% that caused the issue.
Also around that time I was working with TMOUS customer svc to address an issue with my phone constantly disconnecting from mobile data (Solved by manually entering APN data).
I have been able to access the game via my wife's Samsung J8 (same service provider) tethering to the same computer, so feel fairly confident that the issue is within the phone, not settings on my laptop.
Fantasy Grounds tech support doesn't seem to know how to address the issue, so I'm posting here.
I'm not sure, but I think I need help with changing whatever firewall settings the phone may have (I have no third party firewall apps installed), or if I need to adjust something within the APN settings I manually entered.
Thanks in advance, I appreciate any help I can get here.