Symptom
As soon as you connect your VPN tunnel, Skype is not able to make calls any longer, however calls started prior to connecting the VPN continue to work.
Solution
Make sure the field Local Address is not empty. If it is, fill in a private IP address. A private IP address has the following form:
192.168.x.x10.x.x.x172.y.x.x
x: A number of the range 0 to 255.
y: A number of the range 16 to 31.
Only rule: It must not be an IP address from a remote network on the other side of the VPN tunnel (must not partially match an entry of the field "Remote Networks"), as choosing such an address will make the tunnel stop working (it will connect, but you cannot really reach anything over it).
Alternate Solutions
If the solution above does not fix your issues, make sure that
- DNS resolution still works once the VPN tunnel is up.
- Public Internet servers are still reachable once the VPN tunnel is up.
- In case of a Host to Everywhere connection, make sure the VPN gateway does not block any network traffic that is crucial for Skype to work.
Explanation
VPN Tracker creates a virtual tunnel interface for every VPN tunnel. Like any network interface, this virtual tunnel interface requires an IP address to be functional as an IP network interface. If your VPN gateway assigns you an IP address, the assigned address is applied to the tunnel interface. If not, the address you put into Local Address will be used. If you leave local address empty, the IP address of your primary network interface will be used.
In the last case, your system ends up with two interfaces with identical IP addresses. This is allowed and usually not a problem, unless a software does “stupid things”, like querying the network interface for a given IP address and then ignoring the order of precedence of the returned results.
