Linux Server

I have RedHat 9.0 on a machine, 2 NIC’s, one has the ip 195.7.15.x, gateway: 195.7.12.x, DNS: 192.168.x.x (connected to the cable modem), the other 192.168.163.1 (connected to the switch). I’d like to do the following:

1. Route the internal trafic to the internet and viceversa.
2. Set it as a mailserver & webserver & domain server.
3. Allow VPN connections to the LAN.

I’m not asking much, isn’t it? Can anyone help me with a step-by-step guide (I’m new to Linux)?

Thank you.