VPN without static IP address

You need to permit all IP addresses to connect to the VPN Server, or you may can findout the IP range from which SPRINT is assigning dynamic addresses and just allow connections out of this range. I know this is not a proper solution from the security point of view - but the only that will work.

Hope this helps

You did not say if this was a client or the server. Clients do not need a static address if they are the ones originating the VPN connection. The server needs a way to be found, which may or may not be a static address.

If you think about it, a server does not get turned off very often. A DHCP address will change, possibly, on reboot. The other times addresses will change is when the ISP does a massive renumbering of their address blocks to account for growth. (Roadrunner does this a lot.)

One option - list your current IP with a dynamic DNS organization, such as www.dyndns.org. They register a DNS for your dynamic IP. Any time it changes, you hit their site and update the number. There are some others that do this also.

Good luck.