Watchguard Network Security Practice Test

What indicates a failure in IKE phase-2 negotiation based on the log messages provided?

1. Incorrect server address

2. Proposal without PFS

3. Invalid UDP port

4. Outdated firmware

The correct answer is: Proposal without PFS

A failure in IKE phase-2 negotiation can often be indicated by a proposal without Perfect Forward Secrecy (PFS). During the IKE negotiation processes, certain parameters and proposals for how secure the connection should be established are exchanged between the communicating parties. If one side proposes a security parameter set that does not include PFS, which is essential for ensuring that session keys cannot be compromised even if a long-term secret key is exposed, the negotiation can fail. PFS contributes to the security of the VPN tunnel by ensuring that session keys are unique for each session and not dependent on the long-term keying material. When both parties agree on using PFS but a proposal lacks it, this is a mismatch in expectations and can lead to the failure of negotiations. On the other hand, while an incorrect server address or an invalid UDP port may also lead to connection problems, they are typically related to connectivity issues rather than specifically indicating a failure in the IKE phase-2 negotiation process itself. Outdated firmware could influence various aspects of functionality and performance but does not directly relate to specific negotiation parameters in the IKE process.