The answer is to use static NAT for the server and continue using PAT for outbound users. This design is correct because static NAT provides a fixed one-to-one mapping between the public IP and the internal server at 192.168.10.50, ensuring consistent inbound reachability from outside, while PAT allows many inside users to share a single public address for outbound web browsing, conserving the limited public IP pool. On the CCNA 200-301 v2 exam, this question tests your ability to distinguish between address translation methods for different traffic flows—a common trap is assuming one method fits all, but the exam emphasizes that static NAT solves predictability for inbound servers and PAT solves address conservation for outbound clients. Remember the memory tip: "Static for service, PAT for people."
CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. A key principle to apply: static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.. 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.
Users on the inside network can browse the web, but the company now needs an internal web server at 192.168.10.50 to be reachable consistently from outside using one public IP address. Which design is most appropriate?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use static NAT for the server and continue using PAT for user outbound access.
The best design is static NAT for the server while continuing to use PAT for general user outbound traffic. In plain language, user browsing and server publishing are two different requirements. PAT is great for letting many inside users share one public address for outbound access. But a server that outside clients must find reliably needs a fixed one-to-one public identity. That is exactly what static NAT provides.
This is an important design distinction. PAT solves address conservation for many clients. Static NAT solves predictability for inbound access to a specific internal system. The strongest answer is the one that uses each NAT method for the job it fits best.
Key principle: Static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Use static NAT for the server and continue using PAT for user outbound access.
Why this is correct
This is correct because static NAT provides a stable public mapping for the server, while PAT still supports many outbound users.
Related concept
Static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.
✗
Use PAT only for everything, including the published server.
Why it's wrong here
This is wrong because PAT does not provide the same predictable one-to-one public identity expected for a published server.
When this WOULD be correct
In a scenario where all internal services, including web servers, are designed to be accessed externally without needing a consistent IP address for each service, and the organization is comfortable with dynamic port assignments, using PAT for everything could be appropriate.
✗
Disable NAT because private IPv4 addresses are Internet-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 a company is transitioning to IPv6 and has fully migrated its internal network to use public IPv6 addresses, disabling NAT could be correct. The question would specify that the internal web server uses a public IPv6 address, making it routable on the Internet without NAT.
✗
Use DHCP relay for the server to make it reachable from outside.
Why it's wrong here
This is wrong because DHCP relay is unrelated to public reachability for the server.
When this WOULD be correct
If the question were about configuring a network where internal clients need to obtain IP addresses dynamically from a DHCP server located on a different subnet, and the focus was solely on ensuring internal clients can reach the DHCP server, then using DHCP relay would be appropriate.
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.
✓Use static NAT for the server and continue using PAT for user outbound access.Correct answer▾
Why this is correct
This is correct because static NAT provides a stable public mapping for the server, while PAT still supports many outbound users.
✗Use PAT only for everything, including the published server.Wrong answer — click to see why▾
Why this is wrong here
Using PAT only for everything, including the published server, is incorrect because PAT does not allow external users to reach a specific internal server consistently; it translates multiple internal IPs to a single public IP, which can lead to conflicts and accessibility issues.
★ When this WOULD be the correct answer
In a scenario where all internal services, including web servers, are designed to be accessed externally without needing a consistent IP address for each service, and the organization is comfortable with dynamic port assignments, using PAT for everything could be appropriate.
Why candidates choose this
Candidates may choose this option because they understand that PAT is commonly used for outbound connections and might mistakenly believe it can also handle inbound requests effectively without recognizing the limitations for server accessibility.
✗Disable NAT because private IPv4 addresses are Internet-routable.Wrong answer — click to see why▾
Why this is wrong here
Disabling NAT would prevent the internal web server from being accessible from the outside, as private IPv4 addresses are not routable on the Internet. This option fails to meet the requirement of making the server reachable consistently from outside.
★ When this WOULD be the correct answer
In a scenario where a company is transitioning to IPv6 and has fully migrated its internal network to use public IPv6 addresses, disabling NAT could be correct. The question would specify that the internal web server uses a public IPv6 address, making it routable on the Internet without NAT.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of NAT's role in network design, believing that eliminating NAT would simplify access to internal resources without recognizing the implications for private address routing.
✗Use DHCP relay for the server to make it reachable from outside.Wrong answer — click to see why▾
Why this is wrong here
Using DHCP relay does not directly facilitate external access to an internal server; it merely forwards DHCP requests and does not address the requirement for the server to be consistently reachable from outside using a public IP.
★ When this WOULD be the correct answer
If the question were about configuring a network where internal clients need to obtain IP addresses dynamically from a DHCP server located on a different subnet, and the focus was solely on ensuring internal clients can reach the DHCP server, then using DHCP relay would be appropriate.
Why candidates choose this
Candidates might choose this option due to a misunderstanding of DHCP relay's function, confusing it with NAT solutions that manage external access, leading them to think it could help with server reachability.
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 common exam trap is selecting PAT for both outbound and inbound traffic, mistakenly believing PAT can provide a stable public IP for a server. PAT dynamically assigns ports for outbound sessions but does not guarantee a fixed public IP and port combination for inbound connections. This leads to unpredictable external access to the internal server, which fails the requirement for consistent reachability. Another trap is disabling NAT entirely, which ignores that private IPv4 addresses are not routable on the public Internet, making the server unreachable externally. Misunderstanding DHCP relay as a solution for public reachability is also a frequent error, as DHCP relay only forwards DHCP requests and does not affect NAT or routing.
Detailed technical explanation
How to think about this question
Network Address Translation (NAT) is a fundamental IP service that modifies IP address information in packet headers while in transit across a routing device. Static NAT creates a one-to-one mapping between a private internal IP address and a public IP address, allowing external hosts to consistently reach an internal server using a fixed public IP. In contrast, Port Address Translation (PAT) allows multiple internal hosts to share a single public IP address by differentiating sessions using port numbers, which is ideal for outbound client connections but unsuitable for inbound server accessibility.
When designing NAT for a network with both outbound client browsing and inbound server accessibility, the decision hinges on predictability and address conservation. PAT efficiently conserves public IP addresses for outbound traffic by multiplexing many clients behind one IP. However, inbound access to an internal server requires a stable, predictable public IP mapping, which only static NAT can provide. Therefore, the best practice is to use static NAT for the internal web server to ensure consistent external reachability, while continuing to use PAT for general user outbound internet access.
A common exam trap is confusing PAT’s role and assuming it can provide reliable inbound access to a server. PAT dynamically assigns ports and does not guarantee a fixed public IP and port combination for inbound connections, making it unsuitable for hosting services. Additionally, disabling NAT or using DHCP relay does not solve inbound reachability issues; private IPs are not routable on the internet, and DHCP relay only forwards DHCP requests, not public traffic. Understanding these distinctions is critical for correct NAT design and passing the CCNA exam.
KKey Concepts to Remember
Static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.
PAT allows multiple internal clients to share a single public IP address by differentiating sessions with port numbers, optimizing outbound internet access.
Inbound access to internal servers requires static NAT because PAT does not provide predictable public IP and port mappings for external clients.
Private IPv4 addresses are not routable on the public Internet, so NAT is necessary to translate these addresses for external communication.
DHCP relay forwards DHCP requests between clients and servers but does not affect public reachability or NAT mappings.
Using static NAT for servers and PAT for client outbound traffic balances address conservation with predictable inbound access.
PAT is unsuitable for hosting services because it dynamically assigns ports and cannot guarantee a stable public endpoint for inbound connections.
Correct NAT design separates the needs of outbound client browsing and inbound server publishing to ensure both function properly.
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 fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.
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 fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers., 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 fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers..
What is the correct answer to this question?
The correct answer is: Use static NAT for the server and continue using PAT for user outbound access. — The best design is static NAT for the server while continuing to use PAT for general user outbound traffic. In plain language, user browsing and server publishing are two different requirements. PAT is great for letting many inside users share one public address for outbound access. But a server that outside clients must find reliably needs a fixed one-to-one public identity. That is exactly what static NAT provides.
This is an important design distinction. PAT solves address conservation for many clients. Static NAT solves predictability for inbound access to a specific internal system. The strongest answer is the one that uses each NAT method for the job it fits best.
What should I do if I get this 200-301 question wrong?
Review static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Static NAT creates a fixed one-to-one mapping between an internal private IP and a public IP, enabling consistent inbound access to internal servers.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A branch office uses PAT overload on the edge router. Inside users can reach the internet, but return traffic for a newly deployed server must be mapped to a specific inside host. Which two statements are correct?
medium
✓ A.A static NAT entry can provide a consistent public-to-private mapping for the server
✓ B.PAT overload is designed mainly for many-to-one outbound address sharing
C.Dynamic NAT always supports inbound access without additional configuration
D.NAT is unrelated to whether private addresses can reach the public internet
Why A: PAT overload is great for many inside clients sharing a public IP for outbound sessions. A public-facing server that needs predictable inbound reachability typically requires static NAT or static PAT.
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