enable nat on windows xp

***setup information
- wan interface : local area connection
- lan interface: local area connection 2

1- enable ip forward by
run regedit
go to path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
then change the value of
IPEnableRouter=1

2- run the following commands to define nat interface
netsh routing ip nat install
netsh routing ip nat add interface "YOUR INTERNET NIC" full
netsh routing ip nat add interface "YOUR OPEN VPN TAP NIC" private
netsh routing ip nat add interface Internal private

3- start routing and remote access service
net start remoteaccess

or you can find the service in services.msc mmc console

and if the windows xp fail to do the network address translation, just restart the computer,


- we can verify the interface by using the following command

netsh routing ip nat show interface
NAT Internal Configuration
---------------------------
Mode              : Private Interface


NAT Local Area Connection Configuration
---------------------------
Mode              : Address and Port Translation


NAT Local Area Connection 2 Configuration
---------------------------
Mode              : Private Interface