[SOLVED] PC can access "supposedly" blocked website withoutVPN

[gilang0821]

there's no problem but im curious and need an enlightenment? so i use VPN in my PC for couple of years because my ISP blocked some of website. usually i just use VPN for couple of hour then turn it off because the connection were unstable. then suddenly last couple month the "supposedly" blocked website can be accessed without having VPN on, and it only can be done in my PC also they have stable connection. if i use my phone or other devices they will still need use VPN to open block website. so what exactly happen and how can achieve this setting with other devices.

 

[bill001g]

It is likely the difficulty in blocking websites in general.

The first issue is that almost all traffic is now encrypted so you can't actually see what is being done. All you see is the IP addresses. Some attempts are done by trying to intercept the DNS requests so you can see what URL is linked to what IP. This has limited success and DNS can be encrypted by most modern browser when you use DNS providers like cloudflare that support it. Just not using the ISP DNS server makes it much harder on them to intercept the data.

Note DNS filters are also defeated by not using DNS at all and using the host file. What maybe happening is your PC is using a cached DNS entry which creates temporary local copies for short times.

So at this point all you see is the IP addresses. For very small web sites that only have a single IP address you can block IP addresses. Modern web sites uses lots of virtual servers in hosting centers. The IP are many times shared by many different web sites and since servers exist in many different data centers you have way too many IP combinations to block via a simple IP filter.