Network Address Translation Questions and Answers

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Showing 10 of 43 questions
Q31
What does NAT NOT change in packets?
  • A Source IP
  • B Destination IP
  • C MAC address
  • D Source port
Answer: Option C
Explanation: NAT operates at Layer 3; MAC changes only at Layer 2.
Q32
What happens when NAT mapping table is full?
  • A Router crashes
  • B New connections are denied
  • C Old entries get deleted automatically
  • D NAT stops working permanently
Answer: Option B
Explanation: Without available ports/IPs, NAT drops new session attempts.
Q33
Which NAT variant allows the same internal IP to be mapped to different external IPs at different times?
  • A Static NAT
  • B Dynamic NAT
  • C PAT
  • D DNAT
Answer: Option B
Explanation: Dynamic NAT uses a pool; mapping varies based on availability.
Q34
NAT causes which known problem for some applications?
  • A Time synchronization
  • B End-to-end connectivity loss
  • C Increased DHCP scope
  • D Memory leakage
Answer: Option B
Explanation: NAT breaks end-to-end principle, affecting P2P/VoIP.
Q35
NAT traversal is mainly required for which protocol?
  • A SMTP
  • B NTP
  • C VoIP/SIP
  • D HTTPS
Answer: Option C
Explanation: SIP carries IP info in payload, requiring NAT traversal.
Q36
Which NAT operation modifies both IP address and TCP/UDP port?
  • A Static NAT
  • B Port mapping
  • C PAT
  • D Destination NAT
Answer: Option C
Explanation: PAT uses port numbers to differentiate sessions.
Q37
For inbound connections to a server inside NAT, which feature is required?
  • A Port forwarding
  • B RIP updates
  • C DHCP relay
  • D ARP proxy
Answer: Option A
Explanation: Port forwarding opens external ports to internal services.
Q38
Which NAT method is least secure?
  • A PAT
  • B Static NAT
  • C Dynamic NAT
  • D DNAT
Answer: Option B
Explanation: Static NAT exposes one internal machine directly to public IP.
Q39
Which command type is used on routers for NAT configuration?
  • A ip default-network
  • B ip nat inside / ip nat outside
  • C ip helper-address
  • D ip routing
Answer: Option B
Explanation: Interfaces must be marked as inside and outside for NAT.
Q40
Which NAT feature ensures replies return correctly to the original internal host?
  • A Connection tracking
  • B Port mirroring
  • C DHCP lease
  • D Route summarization
Answer: Option A
Explanation: NAT tracks sessions to know where to send response packets.

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