Mapping ISPs Website Blocking Technologies

I think we are all familiar with how websites get blocked in India. Suddenly without notice and reason due to arbitrary court orders which are always in favor of the movie producers who brought these to court. No fact or background checking of any kind is done, all websites mentioned by the producers are blocked and this leads to repercussions such as many legitimate websites getting blocked a recent example being the Internet Archive.

While at present we have no medium to know which websites are blocked what we can do is find what tech the ISPs use in order to block websites. We only need to find this out for the bigger ones as they hold the international gateways and most LOCs and smaller ISPs don't implement their own blocking but rely on the bigger ISPs.

Take for fact my LOC, whenever I visit a blocked website the Airtel DOT notice is shown probably because the LOC uses Airtel's services. And obviously on my Airtel Broadband the Airtel DOT notice is shown.

I was getting restless and annoyed as to how even https:// sites were getting blocked. My post about the same here on this forum led to all of finding out (thanks @Karan) that they use Netsweeper to block websites as do many other ISPs in the Middle East and even in Pakistan. (The details about how the blocking actually happens even for https:// websites can be found in the linked thread).

This is great to know that we have now finally found out what tech is being used by a major ISP and possible workarounds can be found around it. We only have to find this out for a couple more ISPs such as Reliance and Tata and we would have mapped the Telco industry's blocking technologies.

I hope people which see blocking notices from Reliance or TATA or the like can come forward with evidence and we can collaboratively map the blocking tech.

Thank You


I am a n00b
When I was on Nextra for a year, they too blocked websites at the behest of the DoT. I never looked into it in depth, so am not sure the method they used, but, their blocking was a lot more effective, all websites that were blocked, the https trick didn't work on any of them.

Their message was along the lines of what airtel shows for their block page.

Nextra was also notorious for injecting ads into http data streams. They seemed to have dropped that later on.

So, even Hathway is using Netsweeper as confirmed by a user on Reddit: Source

Well the user confirmed it indirectly, in the posted screenshot you can see that Netsweeper is being used clearly: Source

And the user also said they were on Hathway in the comments:

Hathway is still blocking for some reason.


I am a n00b
@Karan Did you try changing the DNS? Could be using DNS blocking. Or maybe even they were using Netsweeper :/
I have always used third party DNS servers, so they were most likely using a filtering system like Netsweeper, if not Netsweeper itself. I never did any digging into it, so can't say.

@RedskyITM Oh Bangalore huh. One reason could be that the regional Hathaway maintainers unblocked it as do many ISPs when they find out that a wrong website has been blocked and the Hathaway Mumbai ones didn't do it.

Another reason could be your DNS settings maybe try with the default DNS and see if the website is still blocked.