The answer is that the IP SLA configuration is missing a source IP address. Without the source-ip command under the icmp-echo configuration, the router defaults to using the IP address of the outgoing interface for the probe packets. This is critical because the path those packets take is determined by the routing table at the moment of transmission, not necessarily the specific path you intend to monitor. On the Cisco CCNP ENARSI 300-410 exam, this tests your understanding that while a source IP is optional, omitting it can lead to misleading results if the outgoing interface changes or if you need to track reachability from a specific loopback or management address. A common trap is assuming the configuration is complete because the destination is set and the schedule is active. Remember the memory tip: "No source, no control"—if you don't specify the source, you lose the ability to guarantee which path is being tested.
300-410 IP SLA Practice Question
This 300-410 practice question tests your understanding of ip sla. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A source IP address is missing; the router will use the outgoing interface IP.
The configuration lacks a source IP address. While optional, without a source-ip, the router uses the outgoing interface IP, which may not be desired for tracking specific paths.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
A source IP address is missing; the router will use the outgoing interface IP.
Why this is correct
Without source-ip, the router defaults to the interface IP used for the route to the destination.
Related concept
Static NAT maps one inside address to one outside address.
✗
The frequency is too low; it should be at least 60 seconds.
Why it's wrong here
Frequency can be as low as 1 second.
✗
The destination IP is invalid; it must be a multicast address.
Why it's wrong here
Destination can be any unicast IP.
✗
The operation type is wrong; it should be udp-echo.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 300-410 question in full detail.
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 300-410 NAT questions on configuration and troubleshooting.
IP SLA — This question tests IP SLA — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: A source IP address is missing; the router will use the outgoing interface IP. — The configuration lacks a source IP address. While optional, without a source-ip, the router uses the outgoing interface IP, which may not be desired for tracking specific paths.
What should I do if I get this 300-410 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 300-410 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
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 →
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. Examine this IP SLA configuration on router R5:
ip sla 50
icmp-echo 10.20.20.1 source-ip 192.168.10.1
frequency 10
ip sla schedule 50 life forever start-time now
What is the effect of this configuration?
medium
✓ A.It will continuously monitor reachability to 10.20.20.1 from source 192.168.10.1.
B.It will stop after 10 successful replies.
C.It will measure jitter between the two IPs.
D.It will only work if 10.20.20.1 is directly connected.
Why A: The configuration creates an IP SLA operation that sends ICMP echo probes to 10.20.20.1 every 10 seconds, using source IP 192.168.10.1. It starts immediately and runs forever.
Variation 2. Given the following partial configuration on router R1:
ip sla 10
icmp-echo 192.168.1.1 source-ip 10.0.0.1
frequency 10
ip sla schedule 10 life forever start-time now
Which statement best describes the effect of this configuration?
medium
✓ A.It sends ICMP echo requests from 10.0.0.1 to 192.168.1.1 every 10 seconds.
B.It sends ICMP echo requests from 192.168.1.1 to 10.0.0.1 every 10 seconds.
C.It sends ICMP echo requests every 10 seconds but only after the first successful reply.
D.It sends ICMP echo requests only once and then stops.
Why A: The configuration creates an IP SLA operation that sends ICMP echo probes to 192.168.1.1 every 10 seconds, using source IP 10.0.0.1. The schedule starts immediately and runs indefinitely.
Variation 3. Given this IP SLA configuration on router R4:
ip sla 40
icmp-echo 10.10.10.1 source-ip 172.16.1.1
frequency 15
ip sla schedule 40 life forever start-time now
Which statement is true?
medium
✓ A.The source IP 172.16.1.1 must be configured on an interface of R4.
B.The source IP 172.16.1.1 can be any IP address, even if not local.
C.The operation will fail because frequency 15 is too high.
D.The operation will use TCP instead of ICMP.
Why A: The configuration sends ICMP echo probes from 172.16.1.1 to 10.10.10.1 every 15 seconds. The source IP is explicitly set.
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Question Discussion
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