Ingress Filtering for Multihomed Networks
RFC 3704

Approval announcement
Draft of message to be sent after approval:

From: The IESG <>
To: IETF-Announce <>
Cc: Internet Architecture Board <>,
    RFC Editor <>
Subject: Protocol Action: 'Ingress Filtering for Multihomed 
         Networks' to BCP 

The IESG has approved the following document:

- 'Ingress Filtering for Multihomed Networks '
   <draft-savola-bcp38-multihoming-update-04.txt> as a BCP

This document has been reviewed in the IETF but is not the product of an
IETF Working Group. 

The IESG contact person is Bert Wijnen.

A URL of this Internet-Draft is:

Technical Summary

  RFC 2827 recommends that ISPs police their customers' traffic by
  dropping traffic entering their networks that is coming from a
  source address not legitimately in use by the customer network.
  The filtering includes but is in no way limited to the traffic
  whose source address is a so-called "Martian Address" - an
  address that is reserved (RFC 3330), including any address
  within,,,,,, or

  This document discusses known technical issues and problems when
  implementing RFC 2827 using:
          o Ingress Access Lists,
          o Strict Reverse Path Forwarding,
          o Feasible Path Reverse Path Forwarding,
          o Loose Reverse Path Forwarding, and
          o Loose Reverse Path Forwarding ignoring default routes

  It also discusses trade-offs and work-arounds available to the
  prudent operator. Ingress filtering issues related to
  multihoming are considered at more length.

Working Group Summary

  As this document is not the product of a working group, there was
  no working group last call.  However, input to the document has 
  been solicited on a number of fora, such as multi6 WG and The 
  North American Network Operators' Group (NANOG) mailing lists.
  There was also a 4 week IETF Last Call.
Protocol Quality
  This document was reviewd for the IESG by Randy Bush, Bert Wijnen
  and the Operations Directorate.