assuming this is windows RRAS server, you may want to use static IP pool. this link may help,
ras error code Receiving RAS error 619 while connecting to a VPN via SBC .... Error 733: the PPP control protocol for this network protocol is not available on the server. ... www.chicagotech.net/raserrors.htm
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
I made ONE successful VPN connection Win2K to XP... now I get 733 error
help...