How to setup VPN on Mac Server 10.7.5 with dyndns router service?

There is this to get you started.

http://www.dummies.com/how-to/content/how-to-configure-vpn-in-lion-server.html

If you get no other replies in this forum try the OS X server forums.

http://www.dummies.com/how-to/content/how-to-configure-lion-server-vpn-clients.h tml

I have not used VPN for a long time, as I said earlier you may get more help in the Server forums.

However the two links I gave at least will help you get started.

To run a public VPN server, you need to do the following:

1. Give the gateway either a static external address or a dynamic DNS name. The latter must be a DNS record on a public DNS registrar, not on the server itself. Also in the latter case, you must run a background process to keep the DNS record up to date when your IP address changes.

2. Give the VPN server a static address on the local network, and a hostname that is not in the top-level domain "local" (which is reserved for Bonjour.)

3. Forward external UDP ports 500, 1701, and 4500 (for L2TP) and TCP port 1723 (for PPTP) to the corresponding ports on the VPN server.

4. Configure any firewall in use to pass this traffic.

That's right.