Cannot establish VPN with error 721 and 800
Situation: 1. The client setup VPN behind
Cisco 678 DMT.
Whenever he tries to establish the VPN, he receives Error 721 or 800.
Troubleshooting: 1. Telnet port 1723 and get respond.
2. We can establish the VPN in the LAN.
PPTPclnt and PPTPsrv to test GRE and PPTP shows the IP Protocol 47 or
GRE is not open.
4. Adding NAT on the Cisco 678 for GRE (set
nat entry add 192.168.0.3 GRE)
fixes the problem.
Refer to case #: JB071806