BCP 84

RFC 8704

Enhanced Feasible-Path Unicast Reverse Path Forwarding, February 2020

File formats:

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Status:
BEST CURRENT PRACTICE
Updates:
RFC 3704
Authors:
K. Sriram
D. Montgomery
J. Haas
Stream:
IETF
Source:
opsec (ops)

Cite this RFC: TXT  |  XML

DOI:  10.17487/RFC8704

Discuss this RFC: Send questions or comments to opsec@ietf.org

Other actions: Submit Errata  |  Find IPR Disclosures from the IETF


Abstract

This document identifies a need for and proposes improvement of the unicast Reverse Path Forwarding (uRPF) techniques (see RFC 3704) for detection and mitigation of source address spoofing (see BCP 38). Strict uRPF is inflexible about directionality, the loose uRPF is oblivious to directionality, and the current feasible-path uRPF attempts to strike a balance between the two (see RFC 3704). However, as shown in this document, the existing feasible-path uRPF still has shortcomings. This document describes enhanced feasible-path uRPF (EFP-uRPF) techniques that are more flexible (in a meaningful way) about directionality than the feasible-path uRPF (RFC 3704). The proposed EFP-uRPF methods aim to significantly reduce false positives regarding invalid detection in source address validation (SAV). Hence, they can potentially alleviate ISPs' concerns about the possibility of disrupting service for their customers and encourage greater deployment of uRPF techniques. This document updates RFC 3704.


For the definition of Status, see RFC 2026.

For the definition of Stream, see RFC 4844.


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