做法：因為 Mac Pro 有二個網路孔，所以讓 pc 能透過 mac 的第二個網路孔連線到 vpn
假設 mac 上的 vpn 設定已經完成。
- Open "System Preferences"
- Select "Sharing"
- Select your VPN connection from the list of "Share your connection from:"
- Select "Ethernet 2" in the checkboxes of "To computers using:"
- Turn on "On" checkbox of "Internet Sharing" from the Service list.
- Connect Ethernet cable between Mac's Port 2 and PC's port
- Connect VPN server in Mac
- Ping a VPN server, to make sure the connection between PC and VPN server is working
