--------VPN MASTER SIDE----------
eth1 (LAN) 192.168.254.0/24
|V|   | Masquerading
|P|   eth0 (WAN) 192.168.0.0/24
|N|   GW 192.168.0.254 (doing DNAT)
| |   Public IP 213.XX.XX.XX
| |   |
| |   |
| |   |
---------- Internet ------------
| |   |
| |   |
| |   |
| |   Public IP 80.XX.XX.XX
|V|   GW 192.168.250.1
|P|   eth0 (WAN) 192.168.250.1/24
|N|   |    Masquerading
eth1 (LAN) 192.168.254.0/24
--------VPN SLAVE SIDE----------