Using the tunnel as a gateway

[Alex]

Hello,

So at school we have to use Cisco AnyConnect VPN software to access
the internet. I used OpenConnect instead and it worked perfectly. The
only thing left was using the computer with the VPN connection as a
gateway for other computers on my network.

What I did was create an ad-hoc network and used the computer with the
VPN connection to NAT all connections. So only one computer is aware
of OpenConnect. All the others computers see a plain old wifi
connection. The computer with the VPN connection has two physical
devies: eth1 and wlan0. wlan0 connects to the network and then
OpenConnection creates the tunnel tun0. eth1 connects to the home
ad-hoc network.

It sort of works, but is very, very screwy. Everything works well on
the the computer with the VPN connection.

On the computers that are connected to the Wifi network, Skype works.
Browsing works on SOME websites. Google works. But some websites
don't. I thought it might be the DNS but I ran a dig and it's
resolving IPs without any problems. IMAP works.

Really lost on this one. Thanks for your help.