I have a test lab environment at home. I have one Cisco 1841 router and a Zyxel Zywall USG 20.The Zywall connects to my ISP. The Cisco router is behind that. The Zywall is on the 10.10.10.0/24 network (10.10.10.1) Router setup:-fa0/0 10.10.10.254 25...