D-Link DFL-CPG310 Product Manual - Page 145

Configuring High Availability Gateway A's priority is 100, and Gateway B's priority is 60. So long as one of Gateway A's Internet connections is up, Gateway A is the Active Gateway, because its priority is higher than that of Gateway B. If both of Gateway A's Internet connections are down, it deducts from its priority 20 (for the primary connection) and 30 (for the secondary connection), reducing its priority to 50. In this case, Gateway B's priority is the higher priority, and it becomes the Active Gateway. You can add individual computers or networks as network objects. This enables you to configure various settings for the computer or network represented by the network object. You can configure the following settings for a network object: • Static NAT (or One-to-One NAT) Static NAT allows the mapping of Internet IP addresses or address ranges to hosts inside the internal network. This is useful if you want a computer in your private network to have its own Internet IP address. For example, if you have both a mail server and a Web server in your network, you can map each one to a separate Internet IP address. Static NAT rules do not imply any security rules. To allow incoming traffic to a host for which you defined Static NAT, you must create an Allow rule. When specifying firewall rules for such hosts, use the host's internal IP address, and not the Internet IP address to which the internal IP address is mapped. For further information, see Using Rules on page 209. Note: Static NAT and Hide NAT can be used together. Note: The NetDefend firewall supports Proxy ARP (Address Resolution Protocol). When an external source attempts to communicate with such a computer, the NetDefend firewall automatically replies to ARP queries with its own MAC address, thereby enabling communication. As a result, the Static NAT Internet IP addresses appear to external sources to be real computers connected to the WAN interface. Chapter 5: Managing Your Network 129