Using a Mac to share a VPN connection

Question

I am using an iMac to share a wired network connection with other devices in my house. I am using Apple's built-in sharing functionality which works very well.

I have also been using Tunnelblick as an OpenVPN client. The two technologies work great when they are not used together.

The moment I connect to my VPN, sharing stops working on all other devices; the whole point of this setup was for me to share my VPN connection.

Is there a way to make Internet connection sharing and OpenVPN work together on the Mac?

I am using Snow Leopard.

Answer 1

The problem sounds like it may be that the VPN server is set to Compulsory Tunneling, which means that no other network connection is allowed except through the VPN.

This is a security measure for which there is no possible workaround, except via changing parameters on the server. More info here.

When Compulsory Tunneling is not set, one can use the local network through Split Tunneling.
See this article as an example of how to set it up : VPN on Mac OS X (Snow Leopard) with Split Tunneling.

Answer 2

Try adding manual routes for requests received through VPN.

Take a look at http://www.macfreek.nl/mindmaster/Modify_PPTP_Routing_Table.

This is so manual but there could be other means as well.