As shown in the figure, if the user wants to use SSH to access the Headquarter S_Site server through the public network, and for security reasons, the destination port number accessed from the…

Question

Options

• ANAPT
• BNAT Server
• CDynamic NAT
• DStatic NAT

• A
  3% (1)
• B
  76% (26)
• C
  6% (2)
• D
  15% (5)

Explanation

NAT Server is the correct choice because it allows administrators to map a specific external IP address and port number to an internal server's IP address and a different port, meaning external users can connect on a non-standard port (e.g., TCP 2200) while the traffic is forwarded to the internal SSH port 22 - satisfying the security requirement that the external-facing port must differ from SSH's default.

NAPT (option A) is designed for many-to-one outbound address translation and does not provide inbound port remapping for specific published services. Dynamic NAT (option C) maps internal addresses to a pool of external addresses for outbound sessions and offers no mechanism to expose an internal server on a custom external port. Static NAT (option D) creates a fixed one-to-one IP mapping but does not translate port numbers, so the destination port would remain 22, violating the security requirement.

Memory tip: NAT Server is the "NAT for servers" - it publishes an internal server to the outside world with full control over both the external and internal port numbers, making it the only type that can remap destination ports on inbound connections.

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