I'm using a dynamic IP address on the linksys router(BEFX41) that is running the DDNS feature to obtain a URL from TZO.COM The VPN is up and working but when a new IP address is assigned from the ISP I lose connectivity on the VPN. I reconfigure the crypto map’s set peer on the 3640 each time to the new IP to bring the tunnel up. How do I configure the Cisco 3640 to accept authentication from the Linksys router when the IP address changes?