Question 790
At Northgate Telecom, the network security operations team administers FortiGate-based protection for a multi-region subscriber service network under requirements for continuous secure intersite connectivity and policy traceability. Following the approved change, the team must validate: Two route-based IPsec peers are online but never pass application traffic because the Phase 2 traffic selectors exclude the new branch subnet. Which observed outcome BEST demonstrates that the intended correction works?
Explanation
Correct Answer
A test flow from the new subnet matches an approved selector and traverses the established IPsec security association. This outcome validates the intended correction for: Two route-based IPsec peers are online but never pass application traffic because the Phase 2 traffic selectors exclude the new branch subnet. The associated approved corrective action is: Update the allowed Phase 2 selectors or supported route-based selector model consistently at both ends of the tunnel. The Northgate Telecom reviewer can therefore distinguish observable protection from an untested configuration claim.
Incorrect Answers
The routing table references the configured tunnel interface and authorized protected traffic follows that tunnel path. This would verify a separate corrective action: Select the FortiGate-supported route-based IPsec tunnel interface design when explicit interface routing is required. That separate change addresses: A team configures a policy-based VPN but expects an automatically created tunnel interface for independent routing rules. It does not validate the current Northgate Telecom issue: Two route-based IPsec peers are online but never pass application traffic because the Phase 2 traffic selectors exclude the new branch subnet. The relevant acceptance evidence is: A test flow from the new subnet matches an approved selector and traverses the established IPsec security association.
A remote application observes the expected original branch source address and an authorized tunnel session remains bidirectional. This would verify a separate corrective action: Remove unintended SNAT on the VPN policy or use the explicitly documented translated-address design if overlap requires it. That separate change addresses: The FortiGate remote-site IPsec policy unintentionally applies internet source NAT to intersite traffic and breaks remote server identity checks. It does not validate the current Northgate Telecom issue: Two route-based IPsec peers are online but never pass application traffic because the Phase 2 traffic selectors exclude the new branch subnet. The relevant acceptance evidence is: A test flow from the new subnet matches an approved selector and traverses the established IPsec security association.
The two trusted peers successfully authenticate and an unrelated peer without the correct secret cannot form the tunnel. This would verify a separate corrective action: Install a securely generated matching preshared secret through the approved tunnel management process on both gateways. That separate change addresses: An IPsec site-to-site tunnel fails IKE authentication because the FortiGate peers use different preshared secrets. It does not validate the current Northgate Telecom issue: Two route-based IPsec peers are online but never pass application traffic because the Phase 2 traffic selectors exclude the new branch subnet. The relevant acceptance evidence is: A test flow from the new subnet matches an approved selector and traverses the established IPsec security association.