Internet through gateway

[masters]

I can't connect from pfsense machine because my provider supports only PPTP VPN connections. That's why I asked my friend (192.168.18.27) to connect my server through gateway(server IP 192.168.18.230)! I've configured an OPT1 connection:
IP adress: 192.168.18.230/23
gateway: 192.168.18.27
In system I've pointed DNS server 192.168.18.254
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There are local network (10.0.0.0) and Internet behind the gateway. From pfsense I see only local network (10.0.0.0) and I can't see the Internet  :-[ From the same machine and same IP from Windows I see both network and Internet. What happens? Maybe I should make more configuration with pfsense???

[hoba]

Could you add some kind of ascii art to describe your setup? would be helpful. I don't understand it yet.