Discuss Cisco 300-410 Exam Topic 15 Question 106

Refer to the exhibit.

A network administrator sets up an OSPF routing protocol for a DMVPN network on the hub router. Which configuration required to establish a DMVPN tunnel with multiple spokes?

Aip ospf network point-to-multipoint on both spoke routers

Bip ospf network point-to-point on the hub router

Cip ospf network point-to-multipoint on One spoke router

Dip ospf network point-to-point on both spoke routers

Suggested Answer: A

Option A configures uRPF loose mode to forward the packet. This mode allows the router to check if there is a route in the routing table that matches the source IP address of the incoming packet, regardless of the interface that is used to reach the source.This mode is suitable for networks that have asymmetric routing, where the incoming and outgoing interfaces for a packet may differ2.

Option B permits the 172.16.3.251 in the inbound ACL on interface gi0/3. This option does not resolve the issue, because it only allows the packet to pass the ACL check, but not the uRPF check.The packet will still be dropped by uRPF if there is no route to reach the source IP address via the same interface3.

Option C permits the 172.16.3.251 in the inbound ACL on interface gi0/3 to allow 172.16.3.251. This option is redundant and incorrect, because it repeats the same IP address twice in the ACL statement.It also does not resolve the issue for the same reason as Option B3.

Option D configures uRPF strict mode to forward the packet. This option does not resolve the issue, because it is the same mode that was already configured on the interface. Strict mode requires that the router has a route to reach the source IP address via the same interface where the packet was received.If this condition is not met, the packet will be dropped4.

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29 comments · newest first

Stephaine 11 months ago

Wait, are we sure about this? Sounds a bit off.

Arthur 11 months ago

No way, point-to-multipoint is the way to go here!

Lemuel 11 months ago

I thought point-to-point was better for spokes?

Luis 11 months ago

Definitely option A! Makes the most sense.

Alberto 12 months ago

OSPF needs point-to-multipoint for DMVPN.

Mitsue 12 months ago

I remember that point-to-multipoint is generally used for spokes, but I can't recall if the hub needs a different setting. This is tricky!

Charlie 1 year ago

I’m a bit confused about whether the hub needs point-to-point or point-to-multipoint. I think I saw something about point-to-point being used on the hub in another practice question.

Jacklyn 1 year ago

I practiced a similar question where we had to choose between point-to-point and point-to-multipoint, and I feel like point-to-multipoint is the right choice for the hub.

Erick 1 year ago

I think I remember that for DMVPN, we usually set OSPF to point-to-multipoint on the spokes, but I'm not entirely sure if it applies to the hub too.

Delsie 1 year ago

This question is testing my knowledge of OSPF and DMVPN configurations. I'll need to carefully analyze each option and think through the network topology to determine the right solution.

Rodolfo 1 year ago

I'm a bit confused by the different OSPF network types mentioned. I'll need to double-check my notes to make sure I understand the differences before selecting an answer.

Hollis 1 year ago

Okay, I've got this. The DMVPN tunnel needs to be point-to-multipoint on the spoke routers, so option A is the correct answer.

Karl 1 year ago

Hmm, the key here seems to be understanding the OSPF network type required for a DMVPN hub-and-spoke topology. I'll need to think through the differences between point-to-point and point-to-multipoint.

Celeste 1 year ago

This looks like a tricky OSPF configuration question. I'll need to carefully review the DMVPN and OSPF network types to determine the right approach.

Jettie 1 year ago

I think Option C is the way to go. Setting one spoke router to point-to-multipoint should allow it to communicate with the hub and other spokes.

Malinda 1 year ago

↳ replying to Jettie

You might be right, having both spoke routers set to point-to-multipoint could improve the network setup.

Annabelle 1 year ago

↳ replying to Jettie

But wouldn't it be better to have both spoke routers set to point-to-multipoint for better communication?

Marcos 1 year ago

↳ replying to Jettie

I agree, Option C seems like the correct choice for setting up the DMVPN tunnel.

Gilberto 1 year ago

Haha, this question is giving me flashbacks to my CCNA days. Remember, kids, always read the documentation carefully!

Yuonne 1 year ago

↳ replying to Gilberto

Option D) ip ospf network point-to-point on both spoke routers

Veda 1 year ago

↳ replying to Gilberto

Option B) ip ospf network point-to-point on the hub router

Lea 1 year ago

↳ replying to Gilberto

Option A) ip ospf network point-to-multipoint on both spoke routers

Rosendo 2 years ago

I see your point, but I think having point-to-multipoint on both spoke routers makes more sense for a DMVPN network.

Gwenn 2 years ago

Hmm, I'm not sure about that. Shouldn't the spoke routers be in a point-to-multipoint configuration to connect to the hub? I'll have to double-check the DMVPN documentation.

Bonita 1 year ago

↳ replying to Gwenn

User 2: Yeah, that makes sense. The spoke routers need to be in a point-to-multipoint configuration to connect to the hub.

Pearlie 1 year ago

↳ replying to Gwenn

User 1: I think it's A) ip ospf network point-to-multipoint on both spoke routers.

Leandro 2 years ago

Option B seems correct, since the DMVPN network requires a point-to-point configuration on the hub router to establish tunnels with multiple spokes.

Devorah 2 years ago

I disagree, I believe the correct answer is B) ip ospf network point-to-point on the hub router.

Rosendo 2 years ago

I think the answer is A) ip ospf network point-to-multipoint on both spoke routers.

Cisco 300-410 Exam - Topic 15 Question 106 Discussion