I have a pfSense box setup as the firewall/router/VPN appliance at my colo.
Once I VPN into the colo (either pptp or openvpn, pptp preferred due to multiple clients and ease of configuration), I am able to hit all my servers by their private 10.10.10.x ip and am able to browse the public internet without issue.
When I try and hit the URL of a domain hosted by one of my servers, I am prompted for credentials. If I login using the pfSense credentials, I'm connected to pfSense as if I'd used it's internal IP. If I hack my hosts file to point url -> server private IP it works fine, but this is obviously not a good solution.
To recap: not connected to VPN -> www.myurl.com works connected to VPN -> www.myurl.com never makes it to the correct server, but is sent only to the pfSense box
I'm sure it's something small that I've missed in the pfSense config.