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Top-level
 On a Mac, you can change the time to live (TTL) for your connection by opening a command prompt (Terminal) and typing these two commands (you'll be asked for an admin password after entering the first of these commands): sudo sysctl -w net.inet.ip.ttl=65 sudo sysctl -w net.inet6.ip6.hlim=65 22 comments
@briankrebs One of the best things about qualifying for FirstNet was true unlimited tethering. This TTL trick is pretty great though.  Thanks for the explanation. I had assumed the throttling happened in the phone, not the tower (or wherever in the phone carrier's network). I was very puzzled why TTL would matter. Personally, I just use Mint Mobile, which gives 5GB of high speed data per month for $15 with no restrictions.  @nitpicking @briankrebs TTL doesn't really matter on a technical basis except that it's a very easy to detect attribute of data packets, one that the equipment is already looking at because it has to adjust it down by one before sending the packet along. On the other hand if you're tethering via USB to a phone speed issues might be due to most phone USB ports only doing USB2 speeds. @fencepost @nitpicking Yes, it apparently matters to some carriers, which seem to use the TTL as a lazy, easy way to restrict the use of their network to devices they (mostly) control.  @fencepost @nitpicking @briankrebs USB2 maxes out at 480Mbps, which I don't think is going to be the limiting factor here. (Also most tethering is probably happening via WiFi hotspot these days.) I've been using Mint Mobile for years. I love telling the Verizon or other sales person at Costco that I pay $15 per month and I just paid for a year. They leave me alone at that point.  @nitpicking @briankrebs Yeah. I appreciate the TTL explanation as I was initially think DNS TTL and going what the ferk? It's also exactly how one would expect a carrier to implement throttling. That is a lame implementation that sort-of, kinda, mostly works. A bit like the bandwidth limits on airport wifi that base it on the MAC address of your NIC.  @briankrebs Sweet! Can we dork with the same setting with a netsh command on Windows? @mjf_pro netsh int ipv4 set glob defaultcurhoplimit=65 netsh int ipv6 set glob defaultcurhoplimit=65  @briankrebs There is a great FOSS tool for detecting such tethering setups on the carrier side: https://en.m.wikipedia.org/wiki/P0f We used it many years ago to detect freeloaders on a dormitory network which had per-user monthly fee. :) I am mentioning it here so that those interested can look at some of the more advanced techniques for passive OS fingerprinting, by examining p0f's source code.  @briankrebs Prior to AT&T joining the GSM world, there were few if any differentiation between native use and tethering. Usage limits were very low anyways.  @jfmezei @briankrebs for what it's worth the different APN setup existed since tethering existed, in Europe. Just a reminder that the world didn't start using mobile internet with the iPhone, even when NORAM might have. @flare2004 @briankrebs I’m in Australia too, and we don’t have tethering limits. Our phone plans are also about a quarter the cost of phone plans in the US. We have it good. Keep quiet. @briankrebs omg, using the TTL as a classifier for a tethered device is sneaky. How would you even start troubleshooting that? What if you set it higher? Do you then get labelled as a hacker? @briankrebs you can change TTL with firewall rules on many LTE routers such as Mikrotik ones. Allows you to use a cheaper pay as you go SIM for data which would normally be restricted to one device: https://help.mikrotik.com/docs/display/ROS/LTE#LTE-Avoidingtetheringspeedthrottling @briankrebs good looks. I've legit been using mobile data in place for home networking since the end of July (right now in my building's lobby) I've been wanting to write notes on my approach but lol kindaaaa curious about The Law (tm) @briankrebs ahh this doesn't seem to work on Linux (cursed phrase, lol) going to look for the equivalent @jalcine You might also need to be running a VPN. See the full instructions at the Reddit link in the OP. |
Gregory's Server
For the uninitiated, changing your computer's TTL won't have a negative effect on it. The TTL basically refers to the max number of network "hops" that a connection can make before it just times out.
The reason this works is that the default TTL for wireless connections is 64, but if you are tethering a computer behind your wireless connection, the tethered computer will be one fewer hops, 63, which allows the carrier to detect you're connecting from something other than your phone. By setting it to 65, your computer will appear to have the correct number of hops indicating a direct connection.
For the uninitiated, changing your computer's TTL won't have a negative effect on it. The TTL basically refers to the max number of network "hops" that a connection can make before it just times out.
The reason this works is that the default TTL for wireless connections is 64, but if you are tethering a computer behind your wireless connection, the tethered computer will be one fewer hops, 63, which allows the carrier to detect you're connecting from something other than your phone. By setting it...