NSE 8 – Network Security Expert (811) — Question 43

A FortiGate with the default configuration shown below is deployed between two IP telephones. FortiGate receives the INVITE request shown in the exhibit from
Phone A (internal) to Phone B (external).
NVITE sip:[email protected]SIP/2.0
Via: SIP/2.0/UDP 10.31.101.20:5060
From: PhoneA <sip:[email protected]>
To: PhoneB <sip:[email protected]>

Call-ID:[email protected]-

CSeq: 1 INVITE -
Contact: sip:[email protected]
v=0
o=PhoneA 5462346 332134 IN IP4 10.31.101.20
c=IN IP4 10.31.101.20
m=audio 49170 RTP 0 3
Which two statements are correct after the FortiGate receives the packet? (Choose two.)

Answer options

• A. NAT takes place only in the SIP application layer.
• B. A pinhole will be opened to accept traffic sent to the FortiGate WAN IP address.
• C. NAT takes place at both the network and SIP application layers.
• D. A pinhole is not required to accept traffic sent to the FortiGate WAN IP address.

Correct answer: B, C

Explanation

The correct answers are B and C. Answer B is correct because a pinhole must be created to handle the incoming SIP traffic directed to the WAN IP, while answer C is accurate as NAT is performed at both the network and SIP application layers for proper handling of the SIP traffic. Answers A and D are incorrect as they misrepresent the NAT process and the requirement for opening a pinhole.