How do you make an internal RFC1918 server reachable on a public IP?

N10-008 By islever Editorial Last updated

Short answer

B Virtual IP

Question

An administrator wants to host services on the internet using an internal server. The server is configured with an RFC1918 address, and the administrator wants to make the services that are hosted on the server available on one of the company's public IP addresses. Which of the following should the administrator configure to allow this access?
  1. IPv6 tunneling
  2. Virtual IP Correct Answer
  3. Dual stack
  4. EUI-64

Key Takeaways

This question tests whether you know that publishing a private IPv4 service on the internet requires a public-IP mapping (VIP/NAT), not IPv6 transition mechanisms.

The correct answer is B: Virtual IP. A Virtual IP (often with NAT/port forwarding) maps an internal server's RFC1918 private address to a public IP, and community discussion agrees that A, C, and D are unrelated.

Common mistake: There was no clearly chosen wrong answer in the voting, but a common misconception is to pick IPv6 tunneling or dual stack because they sound like ways to connect a private network to the internet; in reality these IPv6 transition tools don't translate a private IPv4 address to a public IPv4 address.

Expert Analysis

Why the Answer Is Correct

A Virtual IP address can represent the company's public IP as a mapped address for an internal server configured with an RFC1918 address. When internet clients reach the public IP, the firewall/load balancer uses NAT or port forwarding to forward traffic to the internal private IP. This is the standard way to host an internal service on the internet while keeping the server's private address intact.

Why the Other Options Are Wrong

  • A. IPv6 tunneling only encapsulates one protocol inside another to cross IPv4/IPv6 networks; it has no role in translating a private IPv4 address to a company public IPv4 address.
  • C. Dual stack means running both IPv4 and IPv6 on a host/network simultaneously; it does not make an RFC1918 server reachable on a public IPv4 address.
  • D. EUI-64 is a method for creating an IPv6 interface identifier; it is completely unrelated to publishing a private IPv4 service on the internet.

Community Comment Notes

Commenters all selected B, and [4] explained that a Virtual IP allows network services to be accessible through a public IP and that NAT or port forwarding can map that public IP to the internal server. [2] also noted that the private RFC1918 address and the public IP need to be used simultaneously, which a Virtual IP makes possible. No comments dispute the Virtual IP answer, strengthening the community consensus.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When a question mentions RFC1918 plus a public IP, immediately think NAT, port forwarding, or virtual IP—not IPv6 transition features. Eliminate any IPv6-related option such as tunneling, dual stack, or EUI-64, since the scenario is about IPv4 address translation.

Community Votes

B
100%

100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 5 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 5

  1. tempovpn 👍 27
    Congrats if you saw all 817 questions to pass this exam! I took the exam today and all I can say is, these questions on this website are good. It's like 85~90% same (even answer orders are same). Trust people's opinions in discussion comments, not the original answers cuz there are lots of wrong answers. If you see a 50/50 debate on a question, just google it. You will get the real answer for the question. Good luck, bros.
  2. JB1705 👍 4 Answered B
    RFC1918 is referring to private IP. then you have to use public IP to use Private IP and Public IP simultaneously we will use Virtual IP Virtual IP cz for a single machine to represent multiple IP addresses on the same subnet
  3. e5c1bb5 👍 3 Answered B
    GPT answer seems legit. A, C, and D seem unrelated Using a Virtual IP (VIP) is a common approach to achieve this. A Virtual IP allows network services to be accessible through multiple IP addresses, including public IP addresses, without physically moving the server to a different network. Network Address Translation (NAT) or port forwarding can be used to map the public IP address to the internal server's RFC1918 address.
  4. buscan422 👍 3 Answered B
    He should use Virtual IP address which is NAT service.
  5. Marinos_89 👍 2 Answered B
    A Virtual IP (VIP) allows multiple servers to share the same public IP address, which can be used for various services hosted on an internal server with an RFC1918 (private) address. By configuring a VIP, the administrator can map the internal server's private IP to the public IP address, allowing external clients to access the services hosted on the internal server.

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