Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A company wants a server on the inside network to be reachable consistently from outside using one known public IP address. Which NAT approach best fits that goal?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Static NAT
This is correct because static NAT provides a permanent one-to-one mapping suitable for a reachable internal server.
B
Distractor review
PAT overload only
This is wrong because PAT is mainly intended for many sessions sharing fewer public addresses.
C
Distractor review
No NAT at all, because private IPv4 addresses are Internet-routable
This is wrong because private IPv4 addresses are not Internet-routable.
D
Distractor review
DHCP relay
This is wrong because DHCP relay is unrelated to public reachability through NAT.
Common exam trap
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 outside. PAT is designed for multiple internal clients to share a single public IP for outbound connections, not for providing a fixed public IP to a server. Another common mistake is thinking private IP addresses can be accessed directly from the Internet without NAT, which is incorrect because private IPs are non-routable externally. Misunderstanding DHCP relay as related to NAT or public reachability is also a trap; DHCP relay only forwards DHCP requests and does not affect NAT mappings or external accessibility.
Technical deep dive
How to think about this question
Network Address Translation (NAT) is a fundamental IP service used to translate private IP addresses to public IP addresses, enabling internal devices to communicate with external networks. Static NAT specifically provides a fixed, one-to-one mapping between an internal private IP address and a public IP address. This mapping does not change over time, making it ideal for servers that need to be consistently reachable from the Internet, such as web servers or mail servers. When deciding which NAT method to use, the key consideration is whether the internal device requires a permanent public identity. Static NAT guarantees this by reserving a unique public IP address for the internal server, ensuring external clients always use the same IP to reach it. In contrast, dynamic NAT assigns public IPs from a pool on a first-come, first-served basis, which can change over time and is unsuitable for servers. PAT overload allows many internal hosts to share a single public IP by differentiating sessions with port numbers, but it does not provide a fixed public IP for inbound connections. A common exam trap is confusing PAT overload with static NAT. While PAT is efficient for outbound client traffic, it does not support inbound connections to a specific internal server with a consistent public IP. Another trap is assuming private IP addresses are routable on the Internet, which they are not. Understanding these distinctions is critical for configuring NAT correctly in Cisco environments and for answering CCNA questions accurately. Practically, static NAT simplifies firewall rules and external DNS configurations because the server’s public IP is always known and stable.
KKey Concepts to Remember
- Static NAT creates a permanent one-to-one mapping between a private internal IP address and a public IP address, ensuring consistent external reachability.
- PAT (Port Address Translation) allows multiple internal hosts to share a single public IP address by differentiating sessions using port numbers, but does not provide fixed mappings.
- Private IPv4 addresses are not routable on the public Internet and require NAT to be accessible from outside networks.
- DHCP relay forwards DHCP requests between clients and servers across different IP networks and does not affect NAT or public reachability of internal servers.
- Static NAT is essential when an internal server must be accessible from the Internet using a known, fixed public IP address for services like web hosting or remote access.
- Dynamic NAT maps internal addresses to public addresses from a pool temporarily, which can cause inconsistent external IP mappings for servers.
- PAT overload is optimized for outbound client traffic, not for inbound connections to a specific internal server.
- Using static NAT simplifies firewall and access control configurations because the external IP address of the server is predictable and constant.
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.
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
CCNA subnetting practice questions
Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.
CCNA OSPF practice questions
Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.
CCNA VLAN practice questions
Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.
CCNA STP practice questions
Practise spanning tree, root bridge election, port roles and STP troubleshooting.
CCNA EtherChannel practice questions
Practise LACP, PAgP, port-channel behaviour and bundle requirements.
CCNA ACL practice questions
Practise standard and extended ACLs, permit/deny logic and traffic filtering.
CCNA NAT practice questions
Practise static NAT, dynamic NAT, PAT and inside/outside address translation.
CCNA DHCP practice questions
Practise DHCP scopes, relay, leases and troubleshooting.
CCNA show ip route practice questions
Practise routing-table output, longest-prefix match, AD and route selection.
CCNA show interfaces trunk practice questions
Practise trunk verification and VLAN forwarding across switches.
CCNA wireless security practice questions
Practise WLAN security, authentication and wireless architecture concepts.
CCNA IPv6 practice questions
Practise IPv6 addressing, routes, neighbour discovery and common IPv6 exam traps.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Static NAT creates a permanent one-to-one mapping between a private internal IP address and a public IP address, ensuring consistent external reachability.
What is the correct answer to this question?
The correct answer is: Static NAT — Static NAT best fits that goal because it creates a fixed, predictable one-to-one mapping between the internal server and a public address. In plain language, outside systems always know which public IP represents that server. This predictability is exactly what is needed when a service must be reachable consistently from the outside. PAT is better suited for many outbound clients sharing one address, not for presenting one inside server with a permanent public identity. Dynamic NAT from a pool can also vary depending on design. The correct answer is the one that provides the most stable and direct one-to-one mapping.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
Loading comments…
Sign in to join the discussion.