Some blocked websites won't open even with VPN

In my country many websites like Youtube are blocked. By connecting to a VPN I can access many of them, But some of them still won't work. The loading takes a long time and after some time it shows Timeout Error. I have ubuntu alongside Windows 10, The VPN works perfectly in Windows on the same WiFi network and all websites including Youtube are accessible.

Would that be a DNS problem? (I entered the IP directly and no luck again) If not, What could that be?

P.S. proxy is set to none.

1 Answer

When using PPoE, VPN connection, one common problem is to set correct MTU on the Ethernet connection.

Use ping command to determine your MTU:

ping -M do -s 1472 youtube.com

If the result is (result = "Frag needed and DF set") then go with lower number in the ping command:

ping -M do -s 1462 youtube.com

until you get reply to your ping command (result = reply).

Write down the Number - this will be your MTU.

Now set up the new MTU (your Number) on your ethernet connection as in this question:

How do I change the MTU value on Ubuntu?