TL;DR: if you’re a Sky customer and YouTube suddenly seems a bit broken, have a look at a service called ‘Broadband Shield’. Read about what it’s doing before you turn it off: you may actually want to live with it.
During the week, I started noticing something weird was happening with the DNS on my home network. I don’t have anything vastly complicated set up, but I use pfSense to apply rules to route traffic between three physically separate networks. I’ve had a mess around with DNS configuration before, so that was my first port of call. I tried changing over from Google to CloudFlare to see if that helped, in a just-home-from-work-let’s-poke-a-stick-at-it sort of way. It didn’t. I was able to get access to various sites in the .com domain – and we’re talking imap.google.com, so not exactly off the beaten track – for a while, and then all of a sudden, the names would stop resolving. Oddly enough, I seemed to be having the same problems with my VPN, which I thought offloaded DNS. I didn’t test this thoroughly though.
The real clue came with YouTube, where I was noticing that some videos and all comments were being blocked, and some rendering problems in the app view layout – stuff where there should have been content was blank. Initially I thought this was because Google was delivering content from different domains, and my DNS woes were continuing. Looking at the settings for the YouTube app, the switch for ‘restricted mode’ was greyed out with some text explaining that it had been enabled by the network administrator. Up until this point, I’d have assumed this was me :).
A little bit of googling later to see what sort of parental controls Sky were offering me landed me at the Broadband Shield site. I turned it off, and suddenly all of the name resolution weirdness disappeared, and the YouTube comments were back.
I appreciate the intent with the Shield service but I’d appreciate it a lot more if Sky had told me that they were turning it on, or changing it in a way that would apply a pretty broken policy to name resolution.