I am trying to troubleshoot as to why I am getting the following error when I try log-in to the VPN using Shrew Soft VPN. What doesn't make sense is that it works on the same machine except that in a different ISP. Here's the error.
pre-shared key configured bringing up tunnel ... **negotiation timout occurred** tunnel disabled detached from key daemon
I suspected that it might be the NAT configuration and internal firewall configuration that prevents me from connecting. So, I got a router without any firewall. It didn't work. Now I tried directly connecting to the WAN interface without any in-between network resource going to the internet, it still the same. How do I troubleshoot this further? Anyone who has an experience on it?