Not sure if this has been around for a while or its something I just have’nt noticed but you can now create a IPSEC VPN tunnel with the remote end using a dynamic DNS. I don’t tend to deal much with Dynamic IP’s when it comes to connecting sites.
Previously I just believed Cisco’s did a one time lookup but you can now use the command below to dynamically check the host name each and every time it establishes a connection.
crypto map HostedServer 4 ipsec-isakmp
description **Site to Site VPN**
set peer TEST.dyndns.org dynamic
set transform-set ESP-3DES-SHA
match address VPN