I have the following network configuration:
My PC 192.168.1.20/24 uses 192.168.1.1/24 as a gateway. Dlink-2760U router with Local address 192.168.1.1/24 has a VPN connection open with the provider using PPTP.
Whenever I'm trying to open some web-sites that has some authorization (e.g. gmail.com, coursera.org), I'm getting a request timeout. This problem is observed mostly on linux (Ubuntu 12.04 and Debian 6.0), while most of such websites work correctly on windows XP.
Could you please help me diagnose the problem? Could it be related to NAT + HTTPS?