Share VPN connection with Mountain Lion Server

[velvia]

Hi,

Here is the problem that I would like to solve. I have a connection through my internet provider and a VPN provider (StrongVPN) so I can connect to a server in the USA (I live in France). I would like some of my appliances at home (My TV, my PS3) to access this VPN. But there is no way to configure a VPN on these appliances.

So, I've decided to use this setup :

Router ----(ethernet 1)---> Mac (Mountain Lion Server with VPN configured) ---(ethernet 2)---> Airport Extreme base station ---(WiFi)---> TV, PS3, …

So far, I can't even get internet through the Airport Extereme WiFi even if the VPN on the Mac is not set up. Here are my Preferences :

Ethernet 1:
Configure IPv4 : Using DHCP
IP : 192.168.1.30
Subnet Mask : 255.255.255.0
Router : 192.168.1.1
DNS Server : 192.168.1.1

Ethernet 2:
Configure IPv4 : Using DHCP
IP Address : 169.254.172.87
Subnet Mask : 255.255.0.0
Router : vide
DNS Server : vide

Internet Sharing :
Share your connection from : Ethernet (c'est Ethernet 1)
To computers using : Ethernet (c'est Ethernet 2)

Do you know what's wrong ?