Network Address Translation; Classical Routing - NETGEAR ProSafe FVS336G Reference Manual

ProSafe Dual WAN Gigabit Firewall with SSL & IPsec VPN FVS336G Reference Manual
If you want to use a redundant ISP link for backup purposes, select the WAN port that will act
as the primary link for this mode. Ensure that the backup WAN port has also been configured
and that you configure the WAN Failure Detection Method to support Auto-Rollover.
• Load Balancing Mode. The VPN firewall distributes the outbound traffic equally among the
WAN interfaces that are functional.
Note: Scenarios could arise when load balancing needs to be bypassed for certain
traffic or applications. If certain traffic needs to travel on a specific WAN
interface, configure protocol binding rules for that WAN interface. The rule
should match the desired traffic.
• Single WAN Port Mode. The selected WAN interface is made primary and the other is
disabled.
For whichever WAN mode you choose, you must also choose either NAT or classical routing, as
explained in the following sections.

Network Address Translation

Network Address Translation (NAT) allows all PCs on your LAN to share a single public Internet
IP address. From the Internet, there is only a single device (the VPN firewall) and a single IP
address. PCs on your LAN can use any private IP address range, and these IP addresses are not
visible from the Internet.
• The VPN firewall uses NAT to select the correct PC (on your LAN) to receive any incoming
data.
• If you only have a single public Internet IP address, you MUST use NAT. (the default setting).
• If your ISP has provided you with multiple public IP addresses, you can use one address as the
primary shared address for Internet access by your PCs, and you can map incoming traffic on
the other public IP addresses to specific PCs on your LAN. This one-to-one inbound mapping
is configured using an inbound firewall rule.

Classical Routing

In classical routing mode, the VPN firewall performs routing, but without NAT. To gain Internet
access, each PC on your LAN must have a valid static Internet IP address.
If your ISP has allocated a number of static IP addresses to you, and you have assigned one of
these addresses to each PC, you can choose classical routing. Or, you can use classical routing for
routing private IP addresses within a campus environment.
2-12 Connecting the FVS336G to the Internet
v1.2, June 2008