How to set up vpn port forwarding?

Question

VPN

Good afternoon! There is a vps server on cent os 5.5 with a static ip, vpn is configured on it, however, when connected from a client, it does not allow access to the Internet.
There is a client for this vpn on windows server 2012 r2, ip is dynamic. I am very little familiar with Linux, I set up vpn as it is written here .
How can I do port forwarding from vps server to windows server?
That is, in fact, to make dynamic dns.

Answer 1

www.opennet.ru/docs/RUS/iptables
www.opennet.ru/base/net/nat_redirect.txt.html

Answer 2

I set up vpn according to a new one, now according to this instruction
And now it lets me into the Internet, but what about forwarding, and how to allocate a static local IP to the vpn client, that is, to my home server?