Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
Exhibit
ip flow-export destination 10.99.99.50 2055 ip flow-export source Loopback0 interface Loopback0 ip address 172.16.255.1 255.255.255.255 interface GigabitEthernet0/0 ip address 10.99.99.2 255.255.255.0 Collector subnet: 10.99.99.0/24 Collector accepts exports only from 10.99.99.2
A collector is not receiving flow records from a branch router. Based on the exhibit, what is the most likely issue?
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
Distractor review
The export destination port 2055 is invalid for flow export.
2055 is commonly used for NetFlow collectors.
B
Best answer
The exporter source interface does not match what the collector expects.
Exports are sourced from Loopback0 instead of the accepted 10.99.99.2 address.
C
Distractor review
NetFlow can run only on serial interfaces.
NetFlow is widely used on Ethernet interfaces.
D
Distractor review
The router must use TCP instead of UDP to export flows.
NetFlow exports are commonly sent over UDP.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A common exam trap is to focus on the export destination port or protocol when flow records are not received. Since UDP port 2055 is the default and valid port for NetFlow exports, candidates might incorrectly assume the port is wrong. Another trap is thinking NetFlow only works on serial interfaces, leading to confusion when Ethernet interfaces are used. The real issue often lies in the source interface configuration, where the router exports flow records from an interface IP address that the collector does not expect or trust, causing the collector to drop the data silently.
Technical deep dive
How to think about this question
NetFlow is a Cisco technology used to collect IP traffic information and monitor network flow data. It exports flow records from routers or switches to a collector device, which analyzes traffic patterns for security, performance, or troubleshooting purposes. The export process relies on UDP packets sent from a specific source interface on the router to the collector's IP address and port. The source interface selection is critical because it determines the source IP address used in the export packets, which must be reachable and recognized by the collector. When configuring NetFlow export, the router must use a source interface that has a valid routing path to the collector and matches the IP address expected by the collector for incoming flow records. If the source interface is incorrectly set, the collector may reject or drop the flow records because the source IP address does not match the configured or trusted address. This mismatch causes the collector to not receive or process the flow data, even if the destination IP and port are correct. A common exam trap involves assuming that the export destination port or protocol is the issue, but NetFlow typically uses UDP port 2055 by default, which is valid. Another confusion is thinking NetFlow only runs on certain interfaces like serial, but it works on Ethernet interfaces as well. The practical behavior is that the source interface must be explicitly configured to an interface with a stable and routable IP address, often a loopback interface, to ensure consistent flow export and collector acceptance.
KKey Concepts to Remember
- NetFlow exports flow records using UDP packets from a router's source interface to a collector's IP address and port.
- The source interface for NetFlow export determines the source IP address seen by the collector and must be reachable and trusted.
- Collectors reject flow records if the source IP address does not match the expected or configured address, causing data loss.
- NetFlow commonly uses UDP port 2055 for exporting flow data, which is a valid and standard destination port.
- NetFlow can run on Ethernet interfaces as well as serial interfaces, so interface type does not restrict flow export.
- Configuring the source interface to a loopback interface is a best practice to ensure stable and consistent flow export IP addressing.
- The export destination IP must be correct, but the source interface mismatch is a frequent cause of flow record delivery failure.
- UDP is the transport protocol used for NetFlow exports; TCP is not used for this purpose.
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.
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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?
NetFlow exports flow records using UDP packets from a router's source interface to a collector's IP address and port.
What is the correct answer to this question?
The correct answer is: The exporter source interface does not match what the collector expects. — The exporter is configured to send records out the wrong interface. NetFlow exports must use a source interface that has a valid path to the collector and typically matches the interface the collector expects. The collector IP itself is correct in the example, but the source interface selection is wrong.
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.
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