Examworthy
Open the appSign inStart free

200-301 domain - 25% of the exam

IP Connectivity

IP Connectivity is 25% of the 200-301 exam. These are the objectives it covers, each with practice questions, with every answer explained.

The domain in numbers

83
Practice questions
4
Objectives
59
Medium
24
Hard

Where people go wrong

  • Applying administrative distance before prefix length

    When one destination matches routes of different lengths, the wrong answers rank them by administrative distance, by metric, or by reaching for the default route. Those values only decide between routes to the same prefix. The longest prefix match is applied first, so a /24 beats a /16, a /8 and 0.0.0.0/0 for a destination inside it, whatever the distance. The default route is used only when nothing more specific matches.

    See it in a sample question

  • Giving a floating static route the wrong distance

    A floating static route must carry an administrative distance higher than the route it backs up. The wrong answers choose a lower value such as 90 or 100, leave the default of 1, or match OSPF's 110. A lower or default distance replaces the OSPF route at once, and an equal distance gives no reliable failover. A value such as 130 keeps the static route out of the routing table until the OSPF route is withdrawn.

    See it in a sample question

  • Electing the OSPF DR on router ID instead of priority

    On a broadcast segment the wrong answers elect the designated router by lowest router ID, by lowest priority, or by router ID alone. Interface priority is compared first and the highest value wins. The highest router ID only breaks a tie between equal priorities. A priority of 0 makes a router ineligible for DR or BDR, so a high router ID cannot rescue it.

    See it in a sample question

  • Blaming an OSPF adjacency fault on the wrong stage

    The wrong answers pin an adjacency fault on the wrong stage. Mismatched hello or dead intervals, or a different area ID, reject the neighbour before 2-WAY. An MTU mismatch stalls it later, in EXSTART or EXCHANGE. Two DROTHER routers staying at 2-WAY with each other is the designed state, not a fault. Process IDs are locally significant and never compared between neighbours.

    See it in a sample question

  • Expecting a higher HSRP priority to take over without preempt

    HSRP does not preempt by default. The wrong answers expect a router with a higher priority to take the active role as soon as it appears or rejoins, or blame timers and other settings. An active router keeps the role until it fails unless the higher-priority router has standby preempt configured. Priority decides the initial election, and the higher value wins, but a later takeover needs preempt on the router with the higher priority.

    See it in a sample question

Objectives in this domain

What to study

The official documents this domain's practice questions cite most.

  • Cisco IOS configuration guidecited by 33 questions
  • RFC 2328cited by 25 questions
  • RFC 2281cited by 7 questions
  • RFC 4291cited by 5 questions
  • OSPF DR/BDR electioncited by 1 question
  • RFC 1918cited by 1 question
  • RFC 5798cited by 1 question

Sample questions from this domain

Free sampleIP Connectivitymedium

R1 receives a packet destined for 10.1.5.20. Its IP routing table holds the following three entries, all learned by different means: O 10.1.0.0/16 [110/20] via 10.0.0.2 D 10.1.5.0/24 [90/30720] via 10.0.0.6 S* 0.0.0.0/0 [1/0] via 10.0.0.1 Which entry does R1 use to forward this packet?

R1# show ip route | include 10.1
O    10.1.0.0/16 [110/20] via 10.0.0.2, GigabitEthernet0/0
D    10.1.5.0/24 [90/30720] via 10.0.0.6, GigabitEthernet0/1
S*   0.0.0.0/0 [1/0] via 10.0.0.10
  • AThe EIGRP route 10.1.5.0/24, because it is the most specific entry that contains the destination address Correct
  • BThe OSPF route 10.1.0.0/16, because its administrative distance of 110 is the most trusted of the three entries shown
  • CThe default route 0.0.0.0/0, because its administrative distance of 1 is the lowest value in the table
  • DThe EIGRP route 10.1.5.0/24, because its metric of 30720 is lower than the OSPF metric of 20
A router selects the route with the longest matching prefix first, before administrative distance or metric are considered. Forwarding decisions apply longest prefix match before anything else. The destination 10.1.5.20 is covered by both 10.1.0.0/16 and 10.1.5.0/24, but /24 is more specific than /16, so the EIGRP entry is chosen. Administrative distance and metric only arbitrate between routes that share the same prefix length.

Why A is correct: 10.1.5.20 falls inside 10.1.5.0/24, and a /24 is a longer (more specific) match than the /16, so longest prefix match selects this entry regardless of administrative distance or metric.

Why B is wrong: Administrative distance only breaks a tie between routes to the same prefix; it is not consulted before the longest prefix match, and 110 is in fact a higher (less trusted) value than the EIGRP route's 90.

Why C is wrong: The default route is the shortest possible match and is used only when no more specific entry exists; a lower administrative distance does not let a less specific route win over a longer prefix match.

Why D is wrong: This reaches the right entry but for the wrong reason and gets the comparison backwards; 30720 is not lower than 20, and metrics from different protocols are never compared directly. The deciding factor is the longer prefix.

Free sampleIP Connectivitymedium

R1 learns the 10.20.30.0/24 network from OSPF and you must add a static route over a backup GigabitEthernet link that is used ONLY when the OSPF path fails. Which command installs a floating static route that stays out of the routing table while OSPF is up?

R1# show ip route 10.20.30.0
Routing entry for 10.20.30.0/24
  Known via "ospf 1", distance 110, metric 20
  • Aip route 10.20.30.0 255.255.255.0 192.0.2.2 90
  • Bip route 10.20.30.0 255.255.255.0 192.0.2.2 130 Correct
  • Cip route 10.20.30.0 255.255.255.0 192.0.2.2
  • Dip route 10.20.30.0 255.255.255.0 192.0.2.2 110
A floating static route must be configured with an administrative distance higher than the dynamic route it backs up. A floating static route works by being assigned an administrative distance greater than the primary route's AD. OSPF has a default AD of 110, so a static route needs an AD above 110 to remain dormant until the OSPF route disappears, at which point it installs into the routing table.

Why A is wrong: An AD of 90 is lower than OSPF's 110, so this static route would win and replace the OSPF route immediately rather than floating as a backup.

Why B is correct: An administrative distance of 130 is higher than OSPF's 110, so this route is a backup that only installs when the OSPF route is withdrawn - the definition of a floating static route.

Why C is wrong: Omitting the AD applies the default static distance of 1, which beats OSPF's 110 and takes over the active path instead of backing it up.

Why D is wrong: An AD equal to OSPF's 110 is tempting but does not guarantee a backup: it ties the OSPF route and does not reliably float behind it, so it can be installed alongside or instead of OSPF.

Free sampleIP Connectivityhard

Four routers share one broadcast (Ethernet) segment in OSPF area 0. Their settings are: R1 priority 1, router ID 10.0.0.4; R2 priority 1, router ID 10.0.0.9; R3 priority 0, router ID 10.0.0.20; R4 priority 2, router ID 10.0.0.1. All start at the same instant. Which router becomes the designated router?

  • AR4, because it has the highest interface priority on the segment Correct
  • BR3, because it holds the highest router ID of the four routers
  • CR2, because it has the highest router ID among the priority 1 routers
  • DR1, because the lowest router ID is elected to balance the segment load
Determine the OSPF DR on a multi-access segment by comparing interface priority first and router ID only as a tie-breaker. On broadcast and non-broadcast multi-access networks OSPF elects a DR by the highest interface priority; the highest router ID breaks a tie only when priorities are equal. A priority of 0 removes a router from contention entirely, so R4's priority of 2 wins outright.

Why A is correct: DR election compares OSPF interface priority first; R4's priority of 2 beats the priority 1 of R1 and R2, so it wins before router ID is even considered.

Why B is wrong: Router ID is only the tie-breaker, and R3's priority of 0 makes it ineligible to be DR or BDR regardless of its high router ID.

Why C is wrong: Router ID is consulted only after priority, but R4's higher priority settles the election before any router ID comparison occurs.

Why D is wrong: OSPF never favours the lowest router ID, and R1's priority of 1 is lower than R4's priority of 2 in any case.

Free sampleIP Connectivityhard

Two directly connected routers running OSPFv2 reach the 2-WAY state on a broadcast Ethernet link but never progress to FULL, and the adjacency stays stuck. Which condition best explains why these two non-DR routers remain at 2-WAY rather than this being a fault?

  • AAn MTU mismatch between the two interfaces is holding the routers at 2-WAY until the values agree
  • BTwo DROther routers on a broadcast segment intentionally stay at 2-WAY with each other and form FULL only with the DR and BDR Correct
  • CMismatched hello and dead timers stop the neighbours from advancing beyond 2-WAY until the intervals match
  • DMismatched OSPF area IDs keep the routers at 2-WAY until both interfaces are placed in the same area
On broadcast segments, DROther routers correctly stay at 2-WAY with one another and form full adjacencies only with the DR and BDR. OSPF on broadcast and NBMA networks builds full adjacencies only between DROthers and the DR/BDR to reduce link-state flooding overhead. Two DROther neighbours therefore stop at 2-WAY by design, whereas timer, area, or MTU mismatches block the relationship earlier in the state machine.

Why A is wrong: An MTU mismatch is a real adjacency problem, but it stalls neighbours at EXSTART or EXCHANGE while they exchange database descriptors, not at 2-WAY. It does not explain a stable, expected 2-WAY state.

Why B is correct: On broadcast networks, routers that are neither DR nor BDR (DROthers) deliberately remain at 2-WAY with each other to limit flooding, reaching FULL only with the DR and BDR. This is correct behaviour, not a fault.

Why C is wrong: Mismatched hello or dead timers prevent neighbours from being accepted at all, so they never reach 2-WAY in the first place. They cannot be the cause of a relationship already sitting at 2-WAY.

Why D is wrong: An area-ID mismatch causes hellos to be rejected, so an adjacency never establishes and the neighbour is not seen as 2-WAY. It does not produce a held 2-WAY state.

Free sampleIP Connectivitymedium

An HSRP group has Router1 with priority 110 already active and Router2 with default priority. Router2 is then reconfigured with priority 150, but the network engineer observes that Router1 remains the active router. Which statement explains this behaviour?

  • ARouter1 stays active because HSRP compares router IDs, not priority, once a router is already forwarding for the group
  • BRouter1 stays active because preemption is disabled by default, so the higher-priority Router2 cannot take over the active role Correct
  • CRouter1 stays active because a priority of 150 exceeds the HSRP maximum of 128 and is therefore ignored
  • DRouter1 stays active because the lower-priority router always wins the HSRP election to conserve the higher-priority router
HSRP preemption is off by default, so a higher-priority router will not displace an already-active router unless preempt is configured. When preemption is not enabled, HSRP keeps the current active router in place even if a peer later has a higher priority. Priority only decides the active role at the moment of election or when preemption is explicitly configured, so the higher-priority Router2 stays in standby.

Why A is wrong: HSRP does select the active router by highest priority, not by a router ID, so this misstates the election rule even though it reaches the observed outcome.

Why B is correct: HSRP does not preempt by default, so a router that comes up or is reconfigured with a higher priority waits rather than seizing the active role from an already-active peer.

Why C is wrong: HSRP priority ranges from 0 to 255, so 150 is valid and is not discarded; the real reason Router2 does not take over is the lack of preemption.

Why D is wrong: HSRP favours the higher priority for the active role, not the lower one, so this inverts the rule and does not explain the result.

Other domains in this exam

See also the 200-301 cert hub, the study guide, and the cheat sheet.

Examworthy is not affiliated with or endorsed by Cisco. Original, blueprint-aligned practice material only.