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

8-3
Configuring Network Address Translation (NAT)
Overview
Overview
You can configure the ProCurve Wireless Edge Services xl Module to perform
Network Address Translation (NAT) on traffic routed between two subnet-
works—typically, traffic exchanged between the wireless and the wired net-
work. The module can translate either the source or the destination IP address
in a packet’s IP header to a new address.
The Wireless Edge Services xl Module allows you to implement NAT in several
different ways. For example, you can configure the module to use a single IP
address as the source address for an entire group of wireless stations when
these stations transmit data to a wired network. This implementation of NAT
allows users whose wireless stations have private IP addresses to access the
Internet using one public IP address. NAT also adds another layer of security
by concealing the actual IP addresses of wireless devices from users in the
wired network.
Translating Between an Inside and an Outside Network
When implementing NAT, the Wireless Edge Services xl Module distinguishes
between an inside and an outside network, and implements NAT at the border
between the two networks.
When you configure NAT, you define the inside and outside networks by
specifying if a given virtual LAN (VLAN) interface is inside or outside. For
example, in Figure 8-1, wireless LAN (WLAN) A is assigned to VLAN 8, which
has been defined as an inside interface. On the other hand, VLAN 4, which is
used in the Ethernet LAN, is defined an outside interface.
The setting you select for a particular VLAN—either inside or outside—
depends on how you implement NAT. (The options for implementing NAT are
described in “NAT Implementation Methods” on page 8-5.)