This article describes how I setup an NAT server and an L2TP IPSec VPN server on Gentoo Linux with only one network adapter. Assume
- 12.34.56.78 is the public IP of the server,
- 12.34.56.1 is the gateway of the server,
- 192.168.0.1 is the private IP of the server, and
- 192.168.0.0/24 is the internal network.