Zyxel USG100-PLUS [7/185] Routing and nat

ZyWALL USG Support Notes

1. Routing and NAT

USG ZyWALL is usually placed at the company network boarder, acting as company

network gateway. Routing and NAT are the indispensable functions of USG ZyWALL,

responsible for the routing among intranet networks, as well as comprehensive routing

between intranet and internet traffic. Thus, correctly set up routing and NAT are very

important for the USG ZyWALL to work properly as your requirements.

In the scenario above, there‟re various intranet subnets interconnected. The client

zone and WLAN zone are connected directly to the USG ZyWALL, server zone and

VoIP client subnets are connected to a switch, and the switch is connected to the USG.

All the intranet clients and servers need to be able to access internet, with proper

settings of routing and SNAT. The intranet servers should be able to be accessed by

internet clients, and also should be able to be accessed by the intranet clients. To

enable the branch office intranet clients communicate safely with the HQ internet

resources and clients, IPSec VPN are built between the HQ USG and branch office

security gateway, so correct VPN routing is also necessary. Telecommunicates not

only wants to access the HQ resources via SSL VPN, but also wants to access branch

office resources via SSL VPN first to the HQ, then is directed to the branch office via

IPSec VPN. To achieve this goal, we also need correct routings set on the USG

ZyWALL.