Please consider the following diagram:
The Check Point firewall is a VS on a VSX Cluster running R80.20.
The External interface is assigned a private IP address. But public IP addresses 18.104.22.168/24 are routed to this Check Point firewall.
I need to make a VPN tunnel with a Cisco device with IP 22.214.171.124.
Do you guys have any ideas?
We tried so far to add a dummy interface on the VS that leads to nowhere, but with a Public IP 126.96.36.199. There is a negotiation of the tunnel with the Cisco device, but IKE Phase 1 doesn't go through.
On the Cisco side, we have error messages like:
%CRYPTO-6-IKMP_NOT_ENCRYPTED: IKE packet from 188.8.131.52 was not encrypted and it should've been.
ISAKMP: (1075):retransmitting phase 1 MM_KEY_EXCH...
On Check Point's side we have:
Main Mode Sent Notification to Peer: authentication failed
With a public IP address on the external interface, there is no problem.