Richard writes:
Going back to the real problem... In the short term, I think that the quickest solution is to find out a NAT device which allows inbound traffic to refresh NAT binding timer. I know that cisco PIX is one of them, but would like to find out if any lower end NAT firewall/router have it too...
any cisco ios router, e.g., low end dsl routers, have sip aware nat and you don't need any pinging. pix is cisco firewall and may be too expensive.
-- juha