I suspect my ISP @tatadocomo broadband is throttling/blocking traffic to some sites. Some sites load really slow. I checked speed test & results are fine, but still some websites were not loading properly. So I decided to investigate further.
If I try to open website www.lynda.com it blocks certain GET requests. If you see chrome developer console screenshot you can see some requests getting errors & site is not loading properly
So I suspect ISP is blocking some URLs especially CDN URLs. To confirm this, I hosted an OpenVPN server on AWS cloud and connected to VPN. As I get connected to VPN my ISP cannot see where my internet traffic is going. Its a point to point encrypted tunnel from my computer to AWS VM. So ISP cannot see which domains I am browsing.
On VPN connection www.lynda.com website started working fine. In this next screenshot, you can see open VPN is connected ( Open VPN Orange icon with a green tick ) and the site started working fine.
To confirm, I disconnected VPN. Again the site was getting blocked.
This small test confirms that my ISP either blocks some sites or they have some network issue with their upstream servers/network which does not allow to connect certain sites.
Now that India’s Department of Telecommunications has approved net neutrality rules that ban blocking, throttling, and zero-rating internet data; this act by my ISP may be illegal. I will keep monitoring this behavior and decide next course of action. At the last, I need to switch to a better ISP.