The following is a list of common problems and resolutions that relate to establishing a VPN. Note that any error messages you see in the SmartView Tracker/Log Viewer are documented in the Check Point manuals. Some of the more common errors follow.
Ensure that the appropriate kinds of traffic are being permitted between the two endpoints. If there are any filtering routers along the way, make sure they permit the following protocols:
IP protocols 50 and 51 (for any IPSec-related scheme)
UDP port 500 (for IKE)
Also, you should make sure that NAT is not being performed on any of the packets.
Sometimes you may need to put explicit rules in the firewall permitting ...