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http://www.cisco.com/en/US/products/sw/secursw/ps2308/products_user_guide_chapter09186a008031f1b2.html#wp1006063
Allowing Local LAN Access
In a multiple-NIC configuration, Local LAN access pertains only to network traffic on the interface on which the tunnel was established. The Allow Local LAN Access parameter gives you access to the resources on your local LAN (printer, fax, shared files, other systems) when you are connected through a secure gateway to a central-site VPN device. When this parameter is enabled and your central site is configured to permit it, you can access local resources while connected. When this parameter is disabled, all traffic from your Client system goes through the IPSec connection to the secure gateway.
To enable this feature, check Allow Local LAN Access; to disable it, uncheck the check box. If the local LAN you are using is not secure, you should disable this feature. For example, you would disable this feature when you are using a local LAN in a hotel or airport.
A network administrator at the central site configures a list of networks at the Client side that you can access. You can access up to 10 networks when this feature is enabled. When Allow Local LAN Access is enabled and you are connected to a central site, all traffic from your system goes through the IPSec tunnel except traffic to the networks excluded from doing so (in the network list).
When this feature is enabled and configured on the VPN Client and permitted on the central-site VPN device, you can see a list of the local LANs available by looking at the Routes table. (See Figure 4-5.)
To display the Routes table, use the following procedure:
Cheers Sven