A post-incident review at a regional manufacturing group identifies that an IPsec child SA forms initially but drops at every rekey after peers were configured with incompatible settings. The same control is still uncorrected. Which exposure should the risk register record?
Mismatched Phase 2 security parameters may cause periodic traffic interruption at SA renewal. Phase 2 rekeys must negotiate compatible protection parameters while existing SAs expire. The described exposure follows from leaving the tunnel phase2 rekey mismatch dependency unresolved.
This describes a separate certificate-based VPN peer trust failure. Certificate-based IKE authentication relies on chain validation, identity matching and acceptable certificate validity. It does not identify the most direct consequence of leaving tunnel phase2 rekey mismatch unresolved.
It would be a concern if VPN identity mismatch behind NAT were misconfigured. Here Phase 2 rekeys must negotiate compatible protection parameters while existing SAs expire. The selected alternative does not follow from the observed fault.
This describes a separate IPsec tunnel diagnostics and logging failure. Successful VPN service requires IKE control-plane establishment and verified encrypted bidirectional data-plane traffic. It does not identify the most direct consequence of leaving tunnel phase2 rekey mismatch unresolved.
At a supply-chain company running FortiOS 7.6, a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group. Which configuration or investigative change most directly resolves this issue?
Align both peers' supported Phase 2 perfect forward secrecy settings and DH group selection. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This corrects the FortiGate behavior described by the specific PFS group mismatch fault.
This correction targets wrong remote gateway identity. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. It does not repair the stated PFS group mismatch condition: a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group.
Changing this could help when the fault is NAT traversal UDP 4500, because iPsec NAT-T encapsulates ESP in UDP for compatible paths that cross NAT. Here the evidence instead identifies PFS group mismatch; the recommended correction addresses that dependency.
This correction targets IPsec MTU and MSS fragmentation. IPsec overhead reduces effective payload size and requires correct MTU or MSS handling on constrained paths. It does not repair the stated PFS group mismatch condition: a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group.
During a quarterly security audit, a new FortiGate site cannot create its child SA because one side enables PFS with incompatible DH group settings. What should the FortiGate administrator change to meet the stated requirement?
Align both peers' supported Phase 2 perfect forward secrecy settings and DH group selection. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This corrects the FortiGate behavior described by the specific PFS group mismatch fault.
Changing this could help when the fault is IKE version mismatch, because peers must agree on the IKE protocol and associated negotiation capabilities. Here the evidence instead identifies PFS group mismatch; the recommended correction addresses that dependency.
The proposed setting concerns wrong remote gateway identity, not the actual source of failure. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. It would leave the cited symptom unresolved.
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 PFS group mismatch condition: a new FortiGate site cannot create its child SA because one side enables PFS with incompatible DH group settings.
A municipal network discovers a FortiGate control gap during a segmentation review: a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group; additionally, a new FortiGate site cannot create its child SA because one side enables PFS with incompatible DH group settings. Which targeted correction should the team implement?
Align both peers' supported Phase 2 perfect forward secrecy settings and DH group selection. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This corrects the FortiGate behavior described by the specific PFS group mismatch fault.
This correction targets IKE version mismatch. Peers must agree on the IKE protocol and associated negotiation capabilities. It does not repair the stated PFS group mismatch condition: a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group.
Changing this could help when the fault is redundant tunnel preferences, because redundant VPNs need routing or SD-WAN policy that distinguishes preferred and alternate protected paths. Here the evidence instead identifies PFS group mismatch; the recommended correction addresses that dependency.
The proposed setting concerns preshared key disagreement, not the actual source of failure. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. It would leave the cited symptom unresolved.
The managed services provider team is verifying its fix for an incident where a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group. Which specific observation most convincingly demonstrates the required FortiGate behavior?
Child SA negotiation succeeds with the intended PFS settings visible in peer diagnostics. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This is directly observable evidence for the PFS group mismatch requirement, rather than a generic appliance-health indicator.
That observation is a useful test for wrong remote gateway identity, but not decisive proof of PFS group mismatch. Phase 1 needs a reachable and correctly identified peer, whether statically addressed or dynamically discovered. The recorded acceptance check must demonstrate the actual requirement.
A result about DPD peer liveness can be true while the PFS group mismatch defect persists. DPD detects IKE peer loss when a tunnel stops responding to liveness exchanges. It does not validate the tested dependency.
That observation is a useful test for redundant tunnel preferences, but not decisive proof of PFS group 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.
After a post-upgrade smoke test, administrators correct a problem where a new FortiGate site cannot create its child SA because one side enables PFS with incompatible DH group settings. Which test result should their acceptance record contain?
Child SA negotiation succeeds with the intended PFS settings visible in peer diagnostics. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This is directly observable evidence for the PFS group mismatch requirement, rather than a generic appliance-health indicator.
This verifies a different control: IKE version mismatch. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The stated incident requires evidence of its own packet, identity or policy behavior.
A result about IPsec tunnel diagnostics and logging can be true while the PFS group mismatch defect persists. Successful VPN service requires IKE control-plane establishment and verified encrypted bidirectional data-plane traffic. It does not validate the tested dependency.
This verifies a different control: tunnel phase2 rekey mismatch. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The stated incident requires evidence of its own packet, identity or policy behavior.
An auditor reviewing a research institute deployment finds that a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group. The team claims this is resolved; which concrete evidence would substantiate that claim?
Child SA negotiation succeeds with the intended PFS settings visible in peer diagnostics. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. This is directly observable evidence for the PFS group mismatch requirement, rather than a generic appliance-health indicator.
A result about DPD peer liveness can be true while the PFS group mismatch defect persists. DPD detects IKE peer loss when a tunnel stops responding to liveness exchanges. It does not validate the tested dependency.
That observation is a useful test for IPsec MTU and MSS fragmentation, but not decisive proof of PFS group 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: backup tunnel health validation. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The stated incident requires evidence of its own packet, identity or policy behavior.
If a public library system leaves the following FortiGate issue unresolved—a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group—what is the most direct operational or security consequence?
Incompatible PFS requirements can block Phase 2 while Phase 1 remains healthy. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The described exposure follows from leaving the PFS group mismatch dependency unresolved.
It would be a concern if redundant tunnel preferences were misconfigured. Here PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The selected alternative does not follow from the observed fault.
This describes a separate IPsec tunnel diagnostics and logging failure. Successful VPN service requires IKE control-plane establishment and verified encrypted bidirectional data-plane traffic. It does not identify the most direct consequence of leaving PFS group mismatch unresolved.
That risk is associated with preshared key disagreement rather than the failing PFS group mismatch dependency. A preshared key authenticates the expected IKE peer and must match at both ends. The present scenario establishes a different causal exposure.
During a partner connectivity test, engineers discover that a new FortiGate site cannot create its child SA because one side enables PFS with incompatible DH group settings. What specific failure risk follows if the underlying fault remains?
Incompatible PFS requirements can block Phase 2 while Phase 1 remains healthy. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The described exposure follows from leaving the PFS group mismatch dependency unresolved.
It would be a concern if IPsec tunnel diagnostics and logging were misconfigured. Here PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The selected alternative does not follow from the observed fault.
That risk is associated with DPD peer liveness rather than the failing PFS group mismatch dependency. DPD detects IKE peer loss when a tunnel stops responding to liveness exchanges. The present scenario establishes a different causal exposure.
It would be a concern if NAT traversal UDP 4500 were misconfigured. Here PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The selected alternative does not follow from the observed fault.
A post-incident review at a factory network identifies that a VPN's IKE Phase 1 succeeds but Phase 2 rejects a peer that requires a different PFS group. The same control is still uncorrected. Which exposure should the risk register record?
Incompatible PFS requirements can block Phase 2 while Phase 1 remains healthy. PFS contributes fresh key material to child-SA negotiation and requires peer agreement. The described exposure follows from leaving the PFS group mismatch dependency unresolved.
This describes a separate backup tunnel health validation failure. Redundancy is useful only when both candidate VPN paths can negotiate and forward traffic. It does not identify the most direct consequence of leaving PFS group mismatch unresolved.
That risk is associated with preshared key disagreement rather than the failing PFS group mismatch dependency. A preshared key authenticates the expected IKE peer and must match at both ends. The present scenario establishes a different causal exposure.
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 PFS group mismatch unresolved.
At a retail logistics company running FortiOS 7.6, dynamic peers behind changing public IPs fail authentication because their IKE local IDs no longer match the hub's expected peer ID. Which configuration or investigative change most directly resolves this issue?
Set compatible IKE local and peer ID matching for the supported dynamic site-to-site topology. IKE identity matching is distinct from outer IP addressing and affects dynamic-peer authentication. This corrects the FortiGate behavior described by the specific VPN identity mismatch behind NAT fault.
This correction targets IPsec inter-site firewall policies. IPsec negotiation and FortiGate firewall authorization operate at separate layers. It does not repair the stated VPN identity mismatch behind NAT condition: dynamic peers behind changing public IPs fail authentication because their IKE local IDs no longer match the hub's expected peer ID.
Changing this could help when the fault is preshared key disagreement, because a preshared key authenticates the expected IKE peer and must match at both ends. Here the evidence instead identifies VPN identity mismatch behind NAT; the recommended correction addresses that dependency.
The proposed setting concerns DPD peer liveness, not the actual source of failure. IKE identity matching is distinct from outer IP addressing and affects dynamic-peer authentication. It would leave the cited symptom unresolved.
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