Question 1mediumdrag order
Study the full IPv6 explanation →Question 100 of 2,015
Quick Answer
The answer is that the reply is reverse-translated and sent to the IPv6 host, which is the final step in the NAT64 IPv6-to-IPv4 translation flow. This is correct because NAT64 allows an IPv6-only host to reach an IPv4 server by embedding the IPv4 destination address into a synthesized IPv6 prefix; after the router translates the packet header from IPv6 to IPv4 and forwards it, the return traffic must undergo reverse translation—converting the IPv4 reply back into an IPv6 packet—before it can reach the original IPv6 host. On the ENCOR 350-401 exam, this drag-and-drop question tests your understanding of the complete translation sequence, often with a common trap of placing the reverse translation step too early or confusing it with the initial header translation. A useful memory tip is to think of the flow as “outbound translate, inbound reverse”—the IPv6 host sends, the router translates to IPv4, the reply comes back, and only then does the router reverse-translate back to IPv6.
CCNP NAT and DHCP Practice Question
This 350-401 practice question tests your understanding of nat and dhcp. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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.
Drag and drop the steps of NAT64 IPv6-to-IPv4 translation flow into the correct order, from first to last.
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
IPv6 host sends packet to synthesized IPv6 address
NAT64 allows IPv6-only hosts to reach IPv4 servers. The IPv6 host sends a packet to a synthesized IPv6 address representing the IPv4 destination. The NAT64 router receives the packet and extracts the embedded IPv4 destination address. It translates the packet header from IPv6 to IPv4, including source and destination addresses. The translated IPv4 packet is forwarded to the IPv4 network. When the reply comes back, the router performs reverse translation and sends the IPv6 packet to the host.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-401 NAT questions on configuration and troubleshooting.
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FAQ
Questions learners often ask
What does this 350-401 question test?
NAT and DHCP — This question tests NAT and DHCP — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: IPv6 host sends packet to synthesized IPv6 address — NAT64 allows IPv6-only hosts to reach IPv4 servers. The IPv6 host sends a packet to a synthesized IPv6 address representing the IPv4 destination. The NAT64 router receives the packet and extracts the embedded IPv4 destination address. It translates the packet header from IPv6 to IPv4, including source and destination addresses. The translated IPv4 packet is forwarded to the IPv4 network. When the reply comes back, the router performs reverse translation and sends the IPv6 packet to the host.
What should I do if I get this 350-401 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 350-401 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on 350-401
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. Drag and drop the steps of NAT64 IPv6-to-IPv4 translation flow into the correct order, from first to last.
medium- ✓ A.IPv6 host sends packet to synthetic IPv6 address
- ✓ B.NAT64 router extracts embedded IPv4 destination address
- ✓ C.Router creates NAT64 binding for source IPv6 to IPv4
- ✓ D.Router translates IPv6 header to IPv4 header
- ✓ E.Router forwards translated IPv4 packet to destination
Why A: NAT64 translates IPv6 packets to IPv4. The IPv6 host sends a packet to a synthetic IPv6 address, the router extracts the embedded IPv4 destination, creates a NAT64 binding, translates headers, and forwards the IPv4 packet.
Last reviewed: Jun 18, 2026
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