[rfc-dist] BCP 84, RFC 8704 on Enhanced Feasible-Path Unicast Reverse Path Forwarding

rfc-editor at rfc-editor.org rfc-editor at rfc-editor.org
Fri Feb 7 10:02:02 PST 2020

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        BCP 84        
        RFC 8704

        Title:      Enhanced Feasible-Path Unicast Reverse Path 
        Author:     K. Sriram,
                    D. Montgomery,
                    J. Haas
        Status:     Best Current Practice
        Stream:     IETF
        Date:       February 2020
        Mailbox:    ksriram at nist.gov, 
                    dougm at nist.gov, 
                    jhaas at juniper.net
        Pages:      17
        Updates:    RFC 3704
        See Also:   BCP 84

        I-D Tag:    draft-ietf-opsec-urpf-improvements-04.txt

        URL:        https://www.rfc-editor.org/info/rfc8704

        DOI:        10.17487/RFC8704

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

This document is a product of the Operational Security Capabilities for IP Network Infrastructure Working Group of the IETF.

BCP: This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for 
improvements. Distribution of this memo is unlimited.

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