I have an older Windows 7 test machine which is running Microsoft Security Essentials and pretty much nothing else. Every so often MSE updates its signatures using Windows Update and the BITS services and this seems to work ok. Obviously there aren't any more Updates for W7 (aside from the Malicious Software Removal Tool).
One day I decided to connected this machine to a WiFi hotspot on my phone - this is a p30 lite with a Vodafone sim. This seems fine until MSE tried to update. At which point the BITS service goes a bit nuts - it writes to C:\ProgramData\Microsoft\Network\Downloader\qmgr0.dat continuously until I do a "net stop bits".
This is quite odd. I'm not sure if Windows 10 would have the same issue as I don't use it (I run Linux Mint most of the time). If it does, it would seem like a way to DOS a Windows 10 machine.
Does anyone know if Vodafone filter weird ports or do odd things with their DNS? I remember Three used to filter imgur using a DNS filter but that was easily circumvented and I think they got bored doing that and went away
Edit: That wasn't a particularly well thought out Subject line!