Why is FTP blocked with TMobile One?


    I’ve recently moved from AT&T to TMobile and overall I believe I made the right decision. One unfortunate limitation is that it appears that TMobile is blocking FTP connections. My home router has the ability to access a USB drive over the Internet using FTP with an app like File Explorer for iOS. This has always worked perfectly over AT&T and still works over WiFi, just not TMobile.


    To prove it wasn’t an issue with my routers FTP support I tried another FTP site (speedtest.tele2.net) and got the same Network is Unreachable error. What did work was using a TMobile hotspot on my tablet from my phone. This doesn’t surprise me since tethering is wide open because it is reduced speed or limited data (my tablet has OnePlus, with 10GB of 4G data). Anything on an unlimited One plan is throttled by speed or simply blocking certain ports to reduce data usage.


    I can understand the goal but I think it is unreasonable to disallow FTP transfer. In my case I use far more data loading up web pages than the amount I use to transfer files from my home server.


    I believe I’m on the latest TMobile 31.1 (iPhone 8+) and 31.0 (iPad Pro 10.5).


    Does TMobile have an official statement regarding FTP on their One/Plus unlimited plans?

      All replies

      • snn555

        Re: Why is FTP blocked with TMobile One?

        What you have run into is an iPhone issue.  Example is that my iPhones will not function properly over ipv6 connections, such as my home wifi cameras will not stream over LTE.  Each app has to overcome the issue from Apple.  My Androids have no issues at all.

          • stevenme

            Re: Why is FTP blocked with TMobile One?

            Could be but why would it work when tethered? If I start a hotspot on my iPad Pro (TMobile One Plus), then connect to the hotspot with my iPhone 8 (TMobile One), I can FTP fine. In the past I’ve been told that when going through tethering the BingeOn restrictions of the One plan are disabled. This is because you are effectively under a limited data plan at that point. The One plan tries to limit what you do since theoretically it is unlimited.