What is the purpose of unicast reverse path forwarding?
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A. B. C. D.A
The correct answer is A. to validate packet receipt on interfaces where the traffic should be received.
Unicast reverse path forwarding (uRPF) is a security feature used to prevent IP spoofing attacks by verifying the source address of incoming packets against the routing table. uRPF can be configured on routers to check whether incoming packets are arriving on the expected interface, based on the routing table.
The purpose of uRPF is to ensure that packets arriving on an interface are from a valid source IP address and to prevent traffic with a spoofed source address from entering the network. This technique can help protect against denial-of-service (DoS) attacks and other malicious traffic that may be disguised as legitimate traffic.
When uRPF is enabled on a router, it will verify that the source IP address of incoming packets is reachable via the interface on which the packet was received. If the router determines that the packet's source IP address is not reachable via that interface, the packet will be dropped.
uRPF can be configured in several different modes, including strict mode, loose mode, and VRF mode. In strict mode, the router checks that the source address of a packet matches the interface that the packet was received on. In loose mode, the router allows packets with a source address that matches any interface on the router. In VRF mode, the router performs uRPF checks on a per-VRF basis, allowing for greater flexibility in network design.
In summary, the purpose of uRPF is to verify the source IP address of incoming packets against the routing table to prevent IP spoofing attacks and to ensure that packets are arriving on the expected interface.