To "share" a connection you have to do two things:
- Enable ip-forwarding
- Provide a MASQUERADE rule in iptables.
I don't what, if any, GUI tools might be available for this, but from the command line you could put the following in a startup script (perhaps rc.local
if your distro uses it):
sysctl -w net.ipv4.ip-forward=1
iptables -t nat -A POSTROUTING -i eth0 -o ppp0 -j MASQUERADE
You will also need to make sure that the network interfaces are configured on the machines that will use this. Either you will need to configure them manually (if they aren't already) or else you will need to run a DHCP server.