So what are the needed steps to migrate this old installation from a windows installation to a new Debian installation on a new computer. What are the steps to move the license to the new box? Also the client is thinking to move the ISDN interfaces that he was using to a sip trunk. The problem with this is that the sip trunk comes from a specific lan port on the router and might want a second card on the 3cx or some kind of routing if nat is being involved. From what I have read the 3cx doesn't work well with a second nic and also routing on the box is not recommended. So the only solution is routing on the router?