At this point, it is a global phenomenon (and there's been discussions at the UN General Assembly on carving up interwebs for "security"): https://en.wikipedia.org/wiki/Network_sovereignty

I'm currently reaching it from Spain after a certificate warning. We have our own disgraceful internet access thing going on nationally at the moment, but it doesn't really depend on domains.

In the early days of the IWF blocklist I had trouble with a Joomla install timing out when using my own ISP but it was fine if I used a proxy. It turned out to be because the Joomla install was on cheap GoDaddy hosting, and something on the IWF list was in the same IP block as my hosting - so my ISP was directing traffic through a filtering proxy which was causing problems with Joomla.

(IP address alone isn't enough to identify a particular site, filtering everything for target websie was too expensive, so IP-based filtering was used to decide which traffic went through the filtering proxy.)

The site seems to be blocked for me in the UK, too, by the way.

Depends. It seems Spain is doing interception on the data going from/to IPs, as resolving sci-hub.se with my ISP resolver gives me the same IP as I get when doing it externally (186.2.163.219), but when I visit https://sci-hub.se I see a "Certificate not correct" warning, since the certificate belongs to allot.com, which seems to be the party actually implementing the block here.

If you're on Android you can use Intra from google https://getintra.org/intl/en-GB/#!/

Or if you're on Windows you can use GoodbyeDPI https://github.com/ValdikSS/GoodbyeDPI

Both will split up your dns requests into chunks so the ISPs filter won't catch it.

# poison the DNS: you can use another unaffected DNS to bypass.

# ISP level or country level content filtering (similar to the GFW of China): you need a VPN that won't be blocked, and make sure the exit node is unaffected. (also the police won't care?)

# take down the server: finger cross that they serve the content from safe location.