Ask HN: Is there a way to identify sites blocked by the website visitor's ISP? | Hacker News Reader

Ask HN: Is there a way to identify sites blocked by the website visitor's ISP?

There are countries that block sites for various reasons, India being one of them. If a site is blocked by an ISP you will get a message similar to "The website has been blocked as per direction/order of Hon’ble Court."

Is there a way for me to detect this on a webpage using client side javascript or something? I am working on a site that shows all the sites that are censored/blocked by various ISP's. I can check from my ISP but want to have a site that will allow users to click a button and check sites from a predefined list to see if they are blocked or not by their ISP. The results will then be stored centrally.

Tried searching the web but didn't find any usable ideas on how to achieve this, so any suggestions would be welcome.

View on HN

You may hit some issues with CORS if you're trying to do this on a webpage that you're serving, though the ISP's interference may change this (I'm really not sure, though I wouldn't count on it).

It might work better if you make a TamperMonkey script or some other client-side application that doesn't rely on a browser. In the latter case, it might even be a better idea to have small cloud-base instances set up in various regions around the globe and have them try to access sites directly where they are or use specific ISP proxies (if available) to determine access. Though that could also be a challenge.

Yup, I was hitting issues due to CORS and was wondering if there is a way to avoid them.

I can ask folks to download and install something but if I am doing that then I can might as well ask them to download and run the Python code I have running on my system than install an extension. The idea was to make it as easy as possible to report.

The issue with hosting instances in regions around the globe is that the ISP's I am concerned about are more residential focused than commercial. Another interesting aspect is that the same ISP may be blocking a site in one city but not another so it makes it harder to get data just by running them in data centers around the world

Yeah, you're going to have a tough time getting users to sign up for something like this, regardless of the approach. It might be a good idea to get involved with some online security research interest group since they may have some ideas on how to test this, if not be willing to help you run the experiments so long as you let them see the results.

> the same ISP may be blocking a site in one city but not another I can't say I've heard of this happening very often at all. How common is this? Or is this something you're trying to find out?

Yeah, its hard to get users to download/run code, which is what I had planned to do initially. I have code that I wrote that runs on my local machine to test both ISP's that I use (I have a dual connection) and stores the result.

Then I realized that very few people will download/run code from the internet just to help test the connectivity/blocking status. So, I am trying to figure out a way to do this that makes it as easy as clicking a button by a visitor. But so far haven't had much luck getting it to work as of yet.

Open Rights Group, a UK-based organisation focussed on privacy and free speech run blocked.org.uk, does something like this for UK ISPs. They provide Raspberry Pis which people run from their networks. The devices perform regular requests to various sites to check if any are blocked.

Reply on news.ycombinator.com