I'm not 100% sure I understand your question properly, but I'll give it a shot.
Here's what I think I'm reading in the question:
- Computer at home is normally accessible remotely via HTTP.
- Computer at home is now connected to another network via VPN, and is no longer accessible over HTTP.
If this is an accurate description of the scenario, then your hypothesis is correct - the VPN tunnel is blocking you from accessing your home computer.
The reason this occurs is essentially because the "P" in "VPN" stands for "Private". That means that, once the tunnel is established, the computer or network on one end will only be able to communicate through the computer or network on the other.
To put it another way: If your home computer is connecting over VPN to your work network, the end result is almost exactly (with some variables dependent upon your company's network topology and configuration) as if you'd taken the computer into your office and plugged it into a network port at your desk.
While the tunnel is established, your home computer will only be able to access resources available on your company's network. If your company permits its networked devices to connect to the Internet, your home computer will (usually) also have Internet access while VPN'd to your work network. However, it will likely also be subject to the same Firewall and Proxy restrictions put in place on your company's network.
As long as the VPN is established, you will not likely be able to connect to your home computer from any computer that is not on your company's network. You probably won't even be able to use your home computer to access shared drives and printers on your home LAN, or allow other computers on your home LAN to access the VPN'd computer. Additionally, computers on the Internet at large will not be able to connect to your home computer. Also, it is likely that Firewall/Proxy restrictions will not permit computers from your company's network to connect to your home computer even if they know the IP address assigned to the VPN tunnel.
What is the VPN connecting your computer to? – music2myear – 2011-04-15T19:09:36.840
There are other questions that address this problem, such as: http://superuser.com/questions/29922/2-internet-connections-with-vpn The solution to your problem depends on the VPN software that you're using, but in principle, you want to change your routing settings so that only messages for addresses within your private network go over the VPN. Then your http server will be able to answer requests from the Internet.
– Neil – 2011-04-15T19:27:01.950