VPN ipsec tunnel from router to single windows server computer (gateway-to-host)

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http://serverfault.com – Firstly, is this possible? I haven't seen any posts that talk about this. The situation: 2 different ISP's. One has several servers and a firewall running. The other is limited to only one virtual server with one network card running windows server 2008r2. I need to set up a site-to-site style VPN using IPsec between the firewall of one ISP and the windows host on the other (gateway-to-host). This host has to run a SQL-Server that I can access from the other ISP's servers through the VPN tunnel. It seems looking at the RFC for IPsec that this should be possible using the features of Window (HowTos)