Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

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Configuring Network Address Translation (NAT)
Configuring NAT
3. In the NAT Interface field, use the drop-down menu to select the type of
interfaces to which the module applies NAT:
• Inside (Private)—traffic that arrives from the inside network
In other words, inside NAT applies to incoming traffic on an inside
interface; typically, the inside traffic should be bound to the outside
network.
Internal addresses are those that you are trying to adjust for, or to
conceal from, the outside world, so you will usually select this option
for dynamic source NAT.
• Outside (Public)—traffic that arrives from the outside network
In other words, incoming traffic on an outside interface.
4. In the NAT Address Type field, leave the setting at Source (the only option
permitted for dynamic translation).
The Wireless Edge Services xl Module translates the source addresses of
selected traffic.
5. In the Access List field, use the drop-down menu to select the ACL that
you configured to select traffic.
This ACL should permit the source addresses that you want to translate.
For inside dynamic NAT, the ACL should select inside addresses as they
appear locally (on the inside network). When using outside dynamic NAT,
choose an ACL that selects outside address as they appear on the outside
network. For example, if your outside network is a publicly used wireless
network, the ACL should select traffic from the IP addresses assigned to
wireless stations.
6. From the Interface drop-down menu, select one of the module’s VLAN or
tunnel interfaces.
The Wireless Edge Services xl Module translates the source addresses to
the IP address on the specified interface. Ethernet interfaces are named
vlan1, vlan2, and so on; GRE tunnel interfaces are named tunnel1, tunnel2,
and so on.
If you are configuring dynamic NAT on traffic from wireless stations, make
sure to choose an interface that is tagged on the module’s uplink port. In
this way, return traffic from the wired network can reach the wireless
stations.
The interface you select is sometimes called the overloaded interface
because many devices share its IP address.
7. Click the OK button.