IP Packages are sent out on the wrong network interface.

Issue

IP Packages are sent out on the wrong network interface.

Product Line

TAC Vista

Environment

PC configured to use more than one network interface (Multihomed)

Cause

When a PC should send out a TCP/IP network package to another device it will determine if the destination device is located on the same local network. If it is, the PC can address the message directly to the device's IP address. If it is not, the package need to be sent to a router that can route the message to its final destination using what is called a default gateway. This is normally no problem when the PC is connected to only one network but if it is connected to more than one network that uses gateways to route the traffic on the networks, the PC does not always know which network interface to use for messages that are not addressed to one of the local networks.

Resolution

Tell the PC which routing path to use for a destination address or a destination network. If your PC is configured to use more than one network interface (Multihomed) and your packages are not sent out on the correct network interface, you need to add a routing path for this or those destinations using the "Route ADD" command in Windows via the command prompt.

Example: Add a route path for a network: route add 192.168.2.0 MASK 255.255.255.0 192.168.0.1 ^ 1 ^ 2 ^3
1 = Network address where the devices are located
2 = Network Subnet mask
3 = IP address of the router (gateway) that should be used to forward the packages.

Add a route path per device: route add 192.168.2.25 MASK 255.255.255.255 192.168.0.1 route add 192.168.2.26 MASK 255.255.255.255 192.168.0.1 ^ 1 ^ 2 ^3
1 = IP address of the destination device.
2 = should always be 255.255.255.255
3 = IP address of the router (gateway) that should be used to forward the packages.

For more information of how to use this command, type "route help add" in the command prompt.
Note that added route paths are not persistent by default and will be erased after a system reboot. To make them persistent you need to add the command -p route -p add 192.168........