That only works when you have made special arrangements (policy routing) to make sure the Echolink traffic is ALWAYS sent to the NAT device and never routed directly. See what I explained to Gustavo. That does not require 2 cards (you can put 2 addresses on 1 card), and it is basically the same as the policy routing method, in this case using the IP address as the base for the policy routing. In practice it can be more difficult to implement because you need to force the Echolink application to bind to the correct card address. Fortunately Svxlink can do that, but many other programs cannot. Rob