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300-320 · Question #509

What security feature would require a packet to be received on the interface that the interface would use to forward the return packet?

The correct answer is A. urpf. Unicast Reverse Path Forwarding (uRPF) is a security feature that verifies the source IP address of incoming packets. In strict mode, uRPF checks whether the interface a packet arrives on is the same interface the router would use to forward traffic back to that source address…

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Question

What security feature would require a packet to be received on the interface that the interface would use to forward the return packet?

Options

  • Aurpf
  • Barp inspection
  • Cvlan acl

How the community answered

(60 responses)
  • A
    93% (56)
  • B
    2% (1)
  • C
    5% (3)

Explanation

Unicast Reverse Path Forwarding (uRPF) is a security feature that verifies the source IP address of incoming packets. In strict mode, uRPF checks whether the interface a packet arrives on is the same interface the router would use to forward traffic back to that source address. If the source IP would not be routed back out the same interface, the packet is dropped. This prevents IP spoofing attacks by ensuring the source address is reachable via the ingress interface. ARP inspection validates ARP messages; VLAN ACLs filter traffic within a VLAN - neither checks path symmetry.

Topics

#uRPF#anti-spoofing#unicast reverse path forwarding#interface security

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