RTBH Routing Constraint for Successful Implementation

Routing Constraint for RTBH Implementation

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Question

An engineer is deploying RTBH.

What is necessary routing constraint required for successful implementation?

Answers

A. The trigger device must have an iBGP session with all the clusters/route reflectors in the autonomous system.

B. The trigger device must redistribute the static route pointing to a null interface into the IGP process.

C. The no ip reachables command must be issued on the PE router interface under attack.

D. The attacker`s destination IP address must be routed to a null interface.

E. The eBGP sessions need to set the next-hop attribute value to the trigger device loopback interface.

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Explanations

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A. B. C. D. E.

Explanation : http://www.cisco.com/web/about/security/intelligence/ipv6_rtbh.html Old Dumps Actual Test pg no.52 (520 Q)

RTBH, or Remote Triggered Black Hole, is a method of blocking traffic destined to a target IP address during a DDoS attack by dropping it at the edge of the network. This method is implemented by routing the target IP address to a null interface, effectively dropping the traffic. To successfully implement RTBH, certain routing constraints must be in place.

Out of the given options, option B is the correct answer. The trigger device must redistribute the static route pointing to a null interface into the IGP process. This is necessary because the IGP process distributes routing information to all routers within an autonomous system. By redistributing the static route pointing to a null interface, the trigger device is informing all routers within the autonomous system to drop traffic destined for the target IP address.

Option A is incorrect because having an iBGP session with all the clusters/route reflectors in the autonomous system is not a routing constraint required for successful RTBH implementation. iBGP sessions are used for exchanging routing information within the same autonomous system and for achieving full-mesh connectivity.

Option C is incorrect because the no ip reachables command is not necessary for successful RTBH implementation. This command is used to prevent the router from responding to ICMP echo requests on an interface.

Option D is incorrect because routing the attacker's destination IP address to a null interface is not a routing constraint required for successful RTBH implementation. The purpose of RTBH is to drop traffic destined for the target IP address, not for routing traffic to the attacker's IP address.

Option E is also incorrect because setting the next-hop attribute value to the trigger device loopback interface is not a routing constraint required for successful RTBH implementation. The next-hop attribute specifies the IP address of the next-hop router, which is used to forward the packet to the destination.

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