This issue more relates to network, route, instead of WCF.
When we connect to VPN
, an extra virtual network interface is created on the local machine. At the same time, the local routing table is changed, which caused the issue that the internal network address could not be accessed. We can solve this by setting up a proxy address. A more general way is to set a static route on the local machine.
Route add –p 172.17.10.0 mask 255.255.255.0 172.17.16.1
The first address is a destination network address. the last address is a local gateway, which can be routed by a local network interface. This will lead to the data packages sent to the destination network to be addressed from the specified network interface.
Here is a related link.
https://docs.oracle.com/cd/E53394_01/html/E54745/gmyag.html
Feel free to let me know if there is anything I can help with.