CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company wants an internal web server to be reachable consistently from the Internet using one known public IPv4 address. Which NAT approach best fits that requirement?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Static NAT
Static NAT is the best fit because it creates a fixed one-to-one relationship between the inside server and the public address. In practical terms, outside clients need a stable public identity for the server. They cannot rely on a translated address that changes session by session. Static NAT gives that predictability.
This is different from PAT, which is designed for many inside users sharing fewer public addresses for outbound traffic. The question is about publishing a server, not conserving addresses for client browsing. That is why static NAT is the strongest answer.
Key principle: Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Static NAT
Why this is correct
This is correct because static NAT gives the server a permanent public mapping.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.
✗
PAT overload
Why it's wrong here
This is wrong because PAT is mainly used for many outbound users sharing fewer public addresses.
When this WOULD be correct
If the question specified a scenario where multiple internal devices needed to access the Internet using a single public IP address without requiring consistent external access to a specific internal server, then PAT overload would be the correct choice.
✗
No NAT, because private IPv4 addresses are publicly routable
Why it's wrong here
This is wrong because private IPv4 addresses are not routable on the public Internet.
When this WOULD be correct
In a scenario where the question states that the company has transitioned to using a new IPv6 addressing scheme that allows private addresses to be publicly routable, this option could be correct. The question might specify that the internal web server uses a public IPv6 address, eliminating the need for NAT.
✗
DHCP relay
Why it's wrong here
This is wrong because DHCP relay is unrelated to public reachability of an internal server.
When this WOULD be correct
If the question asked about the need to forward DHCP requests from clients on a different subnet to a DHCP server, then DHCP relay would be the correct answer. This scenario would involve configuring a network where clients cannot directly reach the DHCP server due to subnetting.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Static NATCorrect answer▾
Why this is correct
This is correct because static NAT gives the server a permanent public mapping.
✗PAT overloadWrong answer — click to see why▾
Why this is wrong here
PAT overload allows multiple internal devices to share a single public IP address, but it does not provide a consistent mapping for an internal web server to be reachable from the Internet. This means that the server's address could change, making it unreliable for external access.
★ When this WOULD be the correct answer
If the question specified a scenario where multiple internal devices needed to access the Internet using a single public IP address without requiring consistent external access to a specific internal server, then PAT overload would be the correct choice.
Why candidates choose this
Candidates may choose this option because they understand that PAT allows for efficient use of IP addresses and might mistakenly believe it can also provide consistent access to a specific server.
✗No NAT, because private IPv4 addresses are publicly routableWrong answer — click to see why▾
Why this is wrong here
This option is incorrect because private IPv4 addresses are not routable on the public Internet, making it impossible for an internal web server using a private address to be consistently reachable from the Internet without NAT.
★ When this WOULD be the correct answer
In a scenario where the question states that the company has transitioned to using a new IPv6 addressing scheme that allows private addresses to be publicly routable, this option could be correct. The question might specify that the internal web server uses a public IPv6 address, eliminating the need for NAT.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of private and public IP address functionality, believing that private addresses can be used directly on the Internet without realizing the necessity of NAT for such configurations.
✗DHCP relayWrong answer — click to see why▾
Why this is wrong here
DHCP relay is not relevant to the requirement of making an internal web server reachable from the Internet using a public IP address. It is used for forwarding DHCP requests and responses, not for NAT configurations.
★ When this WOULD be the correct answer
If the question asked about the need to forward DHCP requests from clients on a different subnet to a DHCP server, then DHCP relay would be the correct answer. This scenario would involve configuring a network where clients cannot directly reach the DHCP server due to subnetting.
Why candidates choose this
Candidates may confuse DHCP relay with NAT concepts, thinking that it relates to making services accessible over the Internet, leading them to select it based on a misunderstanding of its purpose in network configurations.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting PAT overload as the solution for making an internal server reachable from the Internet. PAT is primarily designed for outbound traffic from multiple internal hosts sharing a single public IP, not for inbound access to a specific server. Another trap is thinking private IPv4 addresses are publicly routable, which they are not, so no NAT would fail to provide Internet reachability. Also, confusing DHCP relay with NAT functions can mislead candidates, as DHCP relay only forwards DHCP messages and does not affect public IP mappings or server accessibility from the Internet.
Detailed technical explanation
How to think about this question
Network Address Translation (NAT) is a fundamental IP Services technology that modifies IP address information in packet headers while in transit across a routing device. Static NAT specifically maps one private IPv4 address to one public IPv4 address permanently, enabling consistent inbound and outbound communication. This is essential for hosting internal servers that must be reachable from the Internet using a fixed public IP address.
When a company wants an internal web server accessible from the Internet, static NAT is the preferred method because it provides a one-to-one mapping between the internal private IP and a public IP address. This ensures external clients always reach the same public IP, which translates to the internal server's private IP. Unlike PAT (Port Address Translation), which multiplexes many private IPs to a single public IP using different ports, static NAT guarantees a stable, predictable address for inbound connections.
A common exam trap is confusing static NAT with PAT overload or assuming private IP addresses can be routed on the public Internet. Static NAT is necessary for inbound access to internal servers, while PAT is designed for outbound traffic from multiple hosts sharing fewer public IPs. Additionally, DHCP relay is unrelated to NAT and public reachability, as it only forwards DHCP requests across subnets. Understanding these distinctions is critical for correctly answering NAT-related questions on the CCNA exam.
KKey Concepts to Remember
Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.
PAT overload allows multiple private IP addresses to share a single public IP address by using different port numbers, primarily for outbound traffic.
Private IPv4 addresses are not routable on the public Internet and require NAT to enable Internet connectivity.
Static NAT is essential for hosting internal servers that must be reachable from the Internet using a fixed public IP address.
DHCP relay forwards DHCP requests between clients and servers across different subnets but does not affect NAT or public IP address mappings.
PAT is unsuitable for inbound connections to internal servers because it does not provide a fixed public IP mapping.
Static NAT ensures external clients can reliably reach an internal server using a known public IP address.
Confusing static NAT with PAT or assuming private IPs are publicly routable leads to incorrect NAT configurations and exam mistakes.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — This question tests Network Services and Security — Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication..
What is the correct answer to this question?
The correct answer is: Static NAT — Static NAT is the best fit because it creates a fixed one-to-one relationship between the inside server and the public address. In practical terms, outside clients need a stable public identity for the server. They cannot rely on a translated address that changes session by session. Static NAT gives that predictability.
This is different from PAT, which is designed for many inside users sharing fewer public addresses for outbound traffic. The question is about publishing a server, not conserving addresses for client browsing. That is why static NAT is the strongest answer.
What should I do if I get this 200-301 question wrong?
Review static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication., then practise related 200-301 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Static NAT creates a permanent one-to-one mapping between a private IPv4 address and a public IPv4 address for consistent inbound and outbound communication.
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