The answer is that the route is redistributed into OSPF with a metric of 20 and a route tag of 100. This is correct because the Type 5 LSA output shows a metric type of 2 with a value of 20, which is the default cost for routes redistributed from external protocols like EIGRP or BGP, and the External Route Tag of 100 confirms administrative tagging during redistribution. On the Cisco CCNP ENARSI 300-410 exam, this command tests your ability to verify OSPF external routes from redistribution by interpreting the LSA fields, particularly distinguishing between Type 5 and Type 7 LSAs or spotting a non-zero Forward Address, which indicates a different redistribution scenario. A common trap is assuming a metric of 20 always means a directly connected route, but here the Type 2 metric and tag clearly point to redistribution. Memory tip: "Tag 100, metric 20—redistributed, not friendly."
300-410 Route Redistribution Practice Question
This 300-410 practice question tests your understanding of route redistribution. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A network engineer runs the following command to troubleshoot a Route Redistribution issue:
R1# show ip ospf database external
And sees the following output:
OSPF Router with ID (1.1.1.1) (Process ID 1)
Type-5 AS External Link States
LS age: 360
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 192.168.10.0 (External Network Number )
Advertising Router: 2.2.2.2
LS Seq Number: 80000001
Checksum: 0x1234
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 100
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The route is redistributed into OSPF with a metric of 20 and a route tag of 100.
The show ip ospf database external output shows a Type 5 LSA for 192.168.10.0/24, with metric type 2 and metric 20, and external route tag 100. This indicates that the route is redistributed into OSPF from another protocol (likely EIGRP or BGP) by router 2.2.2.2. The tag 100 can be used for filtering.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The route 192.168.10.0/24 is an OSPF internal route.
Why it's wrong here
Type 5 LSAs are external routes, not internal.
✓
The route is redistributed into OSPF with a metric of 20 and a route tag of 100.
Why this is correct
The LSA shows metric type 2, metric 20, and tag 100, typical for redistributed routes.
The forward address is 0.0.0.0, meaning the route is not reachable.
Why it's wrong here
Forward address 0.0.0.0 is normal for Type 5 LSAs; it means the route is reachable via the advertising router.
✗
The route is a default route redistributed into OSPF.
Why it's wrong here
Default route would have Link State ID 0.0.0.0, not 192.168.10.0.
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
OSPF neighbours must agree on key parameters.
Router ID selection can affect neighbour relationships and LSDB output.
OSPF cost influences the preferred path.
A route can appear in OSPF information but not become the installed route.
TExam Day Tips
→Check area mismatch first when OSPF adjacency fails.
→Review passive interfaces when a network is advertised but no neighbour forms.
→Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
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 OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
Route Redistribution — This question tests Route Redistribution — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: The route is redistributed into OSPF with a metric of 20 and a route tag of 100. — The show ip ospf database external output shows a Type 5 LSA for 192.168.10.0/24, with metric type 2 and metric 20, and external route tag 100. This indicates that the route is redistributed into OSPF from another protocol (likely EIGRP or BGP) by router 2.2.2.2. The tag 100 can be used for filtering.
What should I do if I get this 300-410 question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
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