We use an NSA 4500 for our central network edge. One of our sites shares an ASA 55XX (not sure of exact model yet) with a cohabitant and they would like to use it, if they can, to establish a VPN tunnel back to us. Our own support staff have some basic Cisco knowledge but we are more fluent with the NSA series. We have several NSA 220s in the field connecting back to us. The simple answer is "put in an NSA 220", but we'd like to be able to let them use their existing equipment and shared expertise if possible.
I've been searching the net for some time, and have found some dated PIX <-> old Sonicwall version tutorials, but nothing up to date, and nothing that discusses DHCP over VPN (which we use from the NSA 220s to the NSA 4500).
Any constructive thoughts or links to existing relevant documentation would be much appreciated!