I've got a customer who had another consultant swap out their Watchguard Firebox for a Cisco ASA 5510. This customer has 2 subnets behind an internal wireless network that also need to be routed. The consultant who set it up could not get the ASA to route packets back to the two subnets behind the wireless, so he ended up switching the default gateway for the whole organization to the wireless router that was handline the site-to-site wifi, and having it route back to the asa for internet traffic.
This made the wireless unstable, as the device was not designed to handle that much traffic. I got called in to cleanup the mess, and so what I did was put dd-wrt on a linksys befsr41. It was a simple test, and I made that device the router, and had it hand off to the ASA, and put the wireless behind it. This fixed the problem, but the little linksys has introduced a delay to the network.
I know that PIXs could not route internal subnets, and I am assuming this is still the case with an ASA. So what device can I get that is fairly inexpensive and will route to the asa and the two other subnets behind the wireless?