Question 1mediummulti select
Full question →mediummulti selectObjective-mapped
A branch router is running single-area OSPF. An engineer wants an interface to advertise its connected network into OSPF but must prevent hello packets from being sent on that LAN segment. Which two actions achieve 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
Enable OSPF on the interface or matching network statement
OSPF must still be enabled for the connected subnet to be advertised.
B
Best answer
Configure the interface as passive in the OSPF process
Passive-interface stops hello packets while keeping the connected network in the LSDB.
C
Distractor review
Set the interface network type to point-to-point
Changing network type does not suppress hellos.
D
Distractor review
Apply distribute-list out on the interface
A distribute list affects route advertisement policy, not OSPF hello generation on a local segment.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is assuming that changing the OSPF network type or applying a distribute-list on the interface will stop hello packets. Many candidates mistakenly believe that setting the interface to point-to-point suppresses hellos, but it only changes adjacency behavior. Similarly, distribute-lists filter routing updates but do not affect hello packet transmission. The key mistake is forgetting that OSPF must be enabled on the interface to advertise the network and that only the passive-interface command prevents hello packets while still advertising the connected subnet.
Technical deep dive
How to think about this question
OSPF (Open Shortest Path First) is a link-state routing protocol that relies on hello packets to discover and maintain neighbor relationships between routers. These hello packets are multicast periodically on OSPF-enabled interfaces to establish adjacencies and exchange routing information. However, there are scenarios where a router interface must advertise its connected network into OSPF without sending hello packets, such as when the interface connects to end devices or non-OSPF routers. To achieve this, the interface must first be included in the OSPF process by enabling OSPF on the interface or matching it with a network statement. Then, configuring the interface as passive in the OSPF process stops the transmission and reception of hello packets on that interface. This passive-interface setting ensures the connected network is advertised in the OSPF link-state database (LSDB) but prevents OSPF neighbor formation on that segment. This is particularly useful for LAN interfaces connected to hosts or devices that do not participate in OSPF. A common exam trap is confusing passive-interface with other interface settings like changing the network type or applying distribute-lists. Changing the network type (e.g., to point-to-point) does not suppress hello packets, and distribute-lists only filter routing updates, not hello packets. Understanding this distinction is critical for correctly answering questions about controlling OSPF hello packet behavior while still advertising connected networks. In practical networks, passive interfaces reduce unnecessary OSPF traffic and improve stability on LAN segments without OSPF routers.
KKey Concepts to Remember
- OSPF advertises connected networks only if the interface is enabled in the OSPF process or matched by a network statement.
- Configuring an interface as passive in OSPF prevents the sending and receiving of hello packets but still advertises the connected network.
- OSPF hello packets are essential for neighbor discovery and adjacency formation on active interfaces.
- Passive interfaces in OSPF do not form neighbor relationships, which is useful for interfaces connected to end devices or LAN segments without routers.
- Changing the OSPF network type does not suppress hello packets; it only modifies how OSPF treats the interface for adjacency and DR/BDR election.
- Distribute-lists in OSPF control route advertisement filtering but do not affect hello packet transmission on interfaces.
- To advertise a connected network in OSPF, the interface must be included in the OSPF process, either by enabling OSPF on the interface or using a matching network statement.
- Passive-interface configuration is a common method to advertise networks without forming OSPF adjacencies or sending hello packets.
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?
OSPF advertises connected networks only if the interface is enabled in the OSPF process or matched by a network statement.
What is the correct answer to this question?
The correct answer is: Enable OSPF on the interface or matching network statement — In OSPF, a passive interface still advertises the connected network but does not send or process hello packets. So the interface must participate in OSPF, and then it must be made passive.
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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