Hi guys,

In my office I have set up DrayTek Vigor 2820n to be the main internet gateway. The device works perfectly, the Internet connection to the ISP works fine, there are no connection problems, we use VPN clients on our machines to connect to routers in our remote offices without any network problems.

What I want to do next is to successfully establish site to site VPN with the router in one of our offices. That office has Cisco 877 configured as the main gateway, and currently is configured to accept VPN connections from VPN clients (the clients are installed on Windows XP and 7 machines). I followed these setup procedures http://www.draytek.com/user/SupportAppnotesDetail.php?ID=181 for the Cisco router and http://www.draytek.com/user/SupportAppnotesDetail.php?ID=180 for the Vigor router. After I set up the two routers, connection was established.

After the connection was established, it kept on reseting on every minute. This is quite frustrating, as I cannot continue troubleshooting the situation. I am sure the Cisco 877 cannot be the root of the problem, because it was set up for site to site VPN before. Can anyone out there, PLEASE help me with this connectivity problem? Thanks.