If a customer support center leaves the following FortiGate issue unresolved—a new branch establishes Internet access but attempts IPsec to an obsolete public IP for the headquarters firewall—what is the most direct operational or security consequence?
IKE negotiation never reaches the correct peer when the configured remote gateway is wrong. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The described exposure follows from leaving the wrong remote gateway identity dependency unresolved.
That risk is associated with certificate-based VPN peer trust rather than the failing wrong remote gateway identity dependency. Certificate-based IKE authentication relies on chain validation, identity matching and acceptable certificate validity. The present scenario establishes a different causal exposure.
It would be a concern if IKE Phase 1 proposal mismatch were misconfigured. Here Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The selected alternative does not follow from the observed fault.
This describes a separate IPsec inter-site firewall policies failure. IPsec negotiation and FortiGate firewall authorization operate at separate layers. It does not identify the most direct consequence of leaving wrong remote gateway identity unresolved.
During a planned cutover, engineers discover that a peer was replaced and the FortiGate Phase 1 remote-gateway address points to its former WAN endpoint. What specific failure risk follows if the underlying fault remains?
IKE negotiation never reaches the correct peer when the configured remote gateway is wrong. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The described exposure follows from leaving the wrong remote gateway identity dependency unresolved.
This describes a separate redundant tunnel preferences failure. Redundant VPNs need routing or SD-WAN policy that distinguishes preferred and alternate protected paths. It does not identify the most direct consequence of leaving wrong remote gateway identity unresolved.
That risk is associated with certificate-based VPN peer trust rather than the failing wrong remote gateway identity dependency. Certificate-based IKE authentication relies on chain validation, identity matching and acceptable certificate validity. The present scenario establishes a different causal exposure.
It would be a concern if IPsec route to remote subnet were misconfigured. Here Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The selected alternative does not follow from the observed fault.
A post-incident review at a managed services provider identifies that a new branch establishes Internet access but attempts IPsec to an obsolete public IP for the headquarters firewall. The same control is still uncorrected. Which exposure should the risk register record?
IKE negotiation never reaches the correct peer when the configured remote gateway is wrong. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The described exposure follows from leaving the wrong remote gateway identity dependency unresolved.
This describes a separate PFS group mismatch failure. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. It does not identify the most direct consequence of leaving wrong remote gateway identity unresolved.
It would be a concern if IKE Phase 1 proposal mismatch were misconfigured. Here Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The selected alternative does not follow from the observed fault.
This describes a separate IPsec MTU and MSS fragmentation failure. IPsec overhead reduces effective payload size and requires correct MTU or MSS handling on constrained paths. It does not identify the most direct consequence of leaving wrong remote gateway identity unresolved.
At a regional hospital running FortiOS 7.6, IKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered. Which configuration or investigative change most directly resolves this issue?
Align compatible Phase 2 traffic selectors and encryption settings for the intended protected networks. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This corrects the FortiGate behavior described by the specific Phase 2 selector mismatch fault.
This correction targets overlapping VPN subnets. IPsec routing relies on distinct prefixes unless a deliberate translation design separates overlapping address spaces. It does not repair the stated Phase 2 selector mismatch condition: iKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered.
Changing this could help when the fault is backup tunnel health validation, because redundancy is useful only when both candidate VPN paths can negotiate and forward traffic. Here the evidence instead identifies Phase 2 selector mismatch; the recommended correction addresses that dependency.
This correction targets NAT traversal UDP 4500. IPsec NAT-T encapsulates ESP in UDP for compatible paths that cross NAT. It does not repair the stated Phase 2 selector mismatch condition: iKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered.
During an approved policy change, a tunnel negotiates IKE successfully while local and remote protected-subnet selectors no longer agree. What should the FortiGate administrator change to meet the stated requirement?
Align compatible Phase 2 traffic selectors and encryption settings for the intended protected networks. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This corrects the FortiGate behavior described by the specific Phase 2 selector mismatch fault.
Changing this could help when the fault is wrong remote gateway identity, because phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. Here the evidence instead identifies Phase 2 selector mismatch; the recommended correction addresses that dependency.
The proposed setting concerns preshared key disagreement, not the actual source of failure. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. It would leave the cited symptom unresolved.
This correction targets certificate-based VPN peer trust. Certificate-based IKE authentication relies on chain validation, identity matching and acceptable certificate validity. It does not repair the stated Phase 2 selector mismatch condition: a tunnel negotiates IKE successfully while local and remote protected-subnet selectors no longer agree.
A public library system discovers a FortiGate control gap during a planned cutover: IKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered; additionally, a tunnel negotiates IKE successfully while local and remote protected-subnet selectors no longer agree. Which targeted correction should the team implement?
Align compatible Phase 2 traffic selectors and encryption settings for the intended protected networks. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This corrects the FortiGate behavior described by the specific Phase 2 selector mismatch fault.
This correction targets DPD peer liveness. DPD detects IKE peer loss when a tunnel stops responding to liveness exchanges. It does not repair the stated Phase 2 selector mismatch condition: iKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered.
Changing this could help when the fault is PFS group mismatch, because pFS contributes fresh key material to child-SA negotiation and requires peer agreement. Here the evidence instead identifies Phase 2 selector mismatch; the recommended correction addresses that dependency.
The proposed setting concerns tunnel phase2 rekey mismatch, not the actual source of failure. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. It would leave the cited symptom unresolved.
The cloud operations team team is verifying its fix for an incident where IKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered. Which specific observation most convincingly demonstrates the required FortiGate behavior?
Both peers report an established child SA matching the protected local and remote prefixes. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This is directly observable evidence for the Phase 2 selector mismatch requirement, rather than a generic appliance-health indicator.
That observation is a useful test for redundant tunnel preferences, but not decisive proof of Phase 2 selector mismatch. Redundant VPNs need routing or SD-WAN policy that distinguishes preferred and alternate protected paths. The recorded acceptance check must demonstrate the actual requirement.
A result about PFS group mismatch can be true while the Phase 2 selector mismatch defect persists. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. It does not validate the tested dependency.
That observation is a useful test for IPsec inter-site firewall policies, but not decisive proof of Phase 2 selector mismatch. IPsec negotiation and FortiGate firewall authorization operate at separate layers. The recorded acceptance check must demonstrate the actual requirement.
After a new branch activation, administrators correct a problem where a tunnel negotiates IKE successfully while local and remote protected-subnet selectors no longer agree. Which test result should their acceptance record contain?
Both peers report an established child SA matching the protected local and remote prefixes. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This is directly observable evidence for the Phase 2 selector mismatch requirement, rather than a generic appliance-health indicator.
This verifies a different control: overlapping VPN subnets. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The stated incident requires evidence of its own packet, identity or policy behavior.
A result about NAT traversal UDP 4500 can be true while the Phase 2 selector mismatch defect persists. IPsec NAT-T encapsulates ESP in UDP for compatible paths that cross NAT. It does not validate the tested dependency.
This verifies a different control: DPD peer liveness. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The stated incident requires evidence of its own packet, identity or policy behavior.
An auditor reviewing a retail logistics company deployment finds that IKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered. The team claims this is resolved; which concrete evidence would substantiate that claim?
Both peers report an established child SA matching the protected local and remote prefixes. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. This is directly observable evidence for the Phase 2 selector mismatch requirement, rather than a generic appliance-health indicator.
A result about certificate-based VPN peer trust can be true while the Phase 2 selector mismatch defect persists. Certificate-based IKE authentication relies on chain validation, identity matching and acceptable certificate validity. It does not validate the tested dependency.
That observation is a useful test for IPsec MTU and MSS fragmentation, but not decisive proof of Phase 2 selector mismatch. IPsec overhead reduces effective payload size and requires correct MTU or MSS handling on constrained paths. The recorded acceptance check must demonstrate the actual requirement.
This verifies a different control: DPD peer liveness. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The stated incident requires evidence of its own packet, identity or policy behavior.
If an e-commerce platform leaves the following FortiGate issue unresolved—IKE Phase 1 is up but the IPsec child SA cannot form after one site's subnet was renumbered—what is the most direct operational or security consequence?
The IKE control channel may be healthy while the required data-plane IPsec SA is absent. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The described exposure follows from leaving the Phase 2 selector mismatch dependency unresolved.
It would be a concern if tunnel phase2 rekey mismatch were misconfigured. Here Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The selected alternative does not follow from the observed fault.
This describes a separate IPsec inter-site firewall policies failure. IPsec negotiation and FortiGate firewall authorization operate at separate layers. It does not identify the most direct consequence of leaving Phase 2 selector mismatch unresolved.
That risk is associated with wrong remote gateway identity rather than the failing Phase 2 selector mismatch dependency. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The present scenario establishes a different causal exposure.
During a configuration recovery exercise, engineers discover that a tunnel negotiates IKE successfully while local and remote protected-subnet selectors no longer agree. What specific failure risk follows if the underlying fault remains?
The IKE control channel may be healthy while the required data-plane IPsec SA is absent. Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The described exposure follows from leaving the Phase 2 selector mismatch dependency unresolved.
It would be a concern if overlapping VPN subnets were misconfigured. Here Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The selected alternative does not follow from the observed fault.
That risk is associated with IPsec tunnel diagnostics and logging rather than the failing Phase 2 selector mismatch dependency. Successful VPN service requires IKE control-plane establishment and verified encrypted bidirectional data-plane traffic. The present scenario establishes a different causal exposure.
It would be a concern if redundant tunnel preferences were misconfigured. Here Phase 2 selectors and proposals define which traffic the negotiated IPsec data SA protects. The selected alternative does not follow from the observed fault.
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