Hi,

I have a machine which can be accessible through a 3G modem (ppp0 interface) with a public IP.

Now I would like to restrict the connections to the device just to a few number of hosts, all from the same network, maybe two different networks, no more.

So I want to deny every incoming and outgoing connection from and to unwanted hosts, while allowing the trusted hosts to connect.

The main services that will be used will be: webservice and ssh.
I thought to properly configure the firewall, but I am not sure this is the best and right solution.

What is the best network setup solution to my problem ?

Thanks in advance.

Firewall and only allow hosts and ports that you want through.