FCSS_NST_SE-7.6 Exam Dumps : Fortinet NSE 6 - Network Security 7.6 Support Engineer

To capture encrypted IPsec phase 2 (ESP) traffic between two FortiGate devices, the correct protocol filter to use is ip proto 50. According to the Fortinet official sniffing and debugging documentation, ESP (Encapsulating Security Payload) is used for encrypted phase 2 payload transfer and always uses IP protocol number 50. Running the command diagnose sniffer packet any ' ip proto 50 '  captures only ESP packets, which represent the encrypted traffic—whether originating or transiting the device.

If there is no NAT device between FortiGates, ESP is not encapsulated in UDP (thus not on UDP port 4500; if NAT-T were required, packets would be UDP-encapsulated, but the scenario explicitly says NAT is not in use). UDP port 500 is for IKE control (negotiation) traffic, and AH (Authentication Header, ip proto 51) is not used for encryption in standard IPsec phase 2 with ESP.

This matches the official CLI reference from Fortinet for VPN and traffic analysis.

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The correct answer is B .

In the exhibit:

Neighbor 100.64.1.254 shows State/PfxRcd = 1 , which means the session is established and the local FortiGate has received 1 prefix

Neighbor 100.64.2.254 shows State/PfxRcd = Active

The study guide explains the BGP states exactly:

Connect : Waiting for a successful three-way TCP connection

Active : Unable to establish the TCP session

OpenSent : Waiting for an OPEN message from the peer

OpenConfirm : Waiting for the keepalive message from the peer

Established : Peers have successfully exchanged OPEN and keepalive messages

It also explains how to read the State/PfxRcd column:

“If the state is not established, this column displays the BGP state. If the state is established, this column displays the number of prefixes that the local FortiGate received from that neighbor.”

Therefore, because neighbor 100.64.2.254 is in Active state, the correct conclusion is that the BGP adjacency cannot form because the TCP session could not be established .

Why the other options are wrong:

A is wrong because BGP can establish adjacencies with multiple neighbors independently; one established neighbor does not block another

C is wrong because BGP adjacency is not established based on neighbor “priority”; the output shows adjacency is established because the session completed and prefixes were exchanged

D is wrong because having two neighbors in the same remote AS is valid in BGP and does not prevent adjacency formation

So the verified answer is: B .