It shouldn't be the role of the ISP, but in the UK content blocking is legally mandated. E.g., "The Digital Economy Act 2017 placed the requirement for ISP filtering into law and introduced a requirement for ISPs to block pornographic sites with inadequate age verification." https://en.wikipedia.org/wiki/Web_blocking_in_the_United_Kin...
Yeah I'm not sure how much ISPs still bother with that. Up until a year or so ago my ISP was pretty good at blocking torrent sites but now I can visit e.g. 1337x.to with no problems.
I think this is talking about 3's adult content filter which is different and has existed for ages and has always been shit (I assume most people disable it).
How can an ISP be sure an end-to-end encrypted communication channel isn't being used for porn?
It is encrypted. By design they have no idea what it is being used for. It would be very easy to set up a ring of pornography distributors using email (at least in the UK, in civilised countries they'd probably be put out of business by the open internet).
By this interpretation, any TLS channel, even to a supposedly "clean" domain, can be used for porn. Btw, nothing prevents you from emailing porn over Gmail or any of the other "allowed" email providers.
That is not really true, ISPs are relied on by non-technical customers who have neither the personal chops nor a 24/7 technical assistant to help them.
Whether ISPs succeed in any way is an entirely different ballgame, but this is absolutely the job of the ISP, especially in their role of email provider. Its ability to properly discriminate and aggressively block or plonk messages isvery much one of the reasons people like gmail.
> Whether ISPs succeed in any way is an entirely different ballgame, but this is absolutely the job of the ISP, especially in their role of email provider.
They aren't providing email in this example, as far as I can tell. They're providing internet access to an email service. Or they should be.