Hello I am using Windows 7 professional SP1 I am using example that comes with the SDK (Windows7 SDK (x86)) The example is under: C:\Program Files\Microsoft SDKs\Windows\v7.0\Samples\netds\iphelp\iproute I want to create route in internal loop from one port to other port both in local computer I am using with this command line: iproute -a 192.168.0.4 255.255.255.255 192.168.0.3 192.168.0.3 1 The output is: IpRoute: couldn't add (192.168.0.4), dwStatus = 160. I have checked, 160 == ERROR_BAD_ARGUMENTS That things works fine in windows XPyoavk

Hi, In Windows 7, system will help you choose a most proper source IP based on the strong host model so that this route cannot be added in route list. For more information, please see the following blog. http://blogs.technet.com/b/networking/archive/2009/04/25/source-ip-address-selection-on-a-multi-homed-windows-computer.aspxJuke Chou TechNet Community Support