Question 1190
At Oakmont Insurance, the FortiGate 7.6 security administration team encounters the following authorized operational case: two acquired offices use the same protected subnet and the hub FortiGate cannot distinguish return destinations across their VPNs. They need a defensible FortiOS configuration, diagnosis, validation or prevention decision. What root condition most directly explains the described FortiGate symptom?
Explanation
Correct Answer
Identical remote prefixes cannot be unambiguously routed to separate IPsec site destinations. The mechanism is relevant because the stated ipsec overlapping address conflict incident concerns the actual selected path, policy, identity or inspection state. The appropriate response is to readdress one protected network or design compatible selective translation with nonoverlapping tunnel selectors; verify it through this observed condition: a test reaches both offices through distinct documented translated destinations.
Incorrect Answers
An established IPsec tunnel does not override FortiGate forward-policy enforcement explains a different situation, route-based tunnel interface policy, where a route-based IPsec tunnel is up but users cannot reach the remote LAN because no firewall policy permits the tunnel interface pair. It does not account for the specific observed ipsec overlapping address conflict condition at Oakmont Insurance. The decisive mechanism here is: Identical remote prefixes cannot be unambiguously routed to separate IPsec site destinations.
An accepting outbound policy does not necessarily create permission for independently initiated inbound flows explains a different situation, ipsec tunnel policy return direction, where the head office reaches a remote file server but the remote office cannot initiate sessions toward the head-office database. It does not account for the specific observed ipsec overlapping address conflict condition at Oakmont Insurance. The decisive mechanism here is: Identical remote prefixes cannot be unambiguously routed to separate IPsec site destinations.
A wizard's initial example selectors and permit addresses may not match every required protected network explains a different situation, vpn wizard group policy permissions, where a newly created wizard tunnel is reachable from one internal subnet but the wizard-generated policy does not include the second authorized subnet. It does not account for the specific observed ipsec overlapping address conflict condition at Oakmont Insurance. The decisive mechanism here is: Identical remote prefixes cannot be unambiguously routed to separate IPsec site destinations.