RFC 3704 (rfc3704) - Page 2 of 16

Ingress Filtering for Multihomed Networks

RFC 3704       Ingress Filtering for Multihomed Networks      March 2004


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Different Ways to Implement Ingress Filtering  . . . . . . . .  4
       2.1 Ingress Access Lists . . . . . . . . . . . . . . . . . . .  4
       2.2 Strict Reverse Path Forwarding . . . . . . . . . . . . . .  5
       2.3 Feasible Path Reverse Path Forwarding  . . . . . . . . . .  6
       2.4 Loose Reverse Path Forwarding  . . . . . . . . . . . . . .  6
       2.5 Loose Reverse Path Forwarding Ignoring Default Routes  . .  7
   3.  Clarifying the Applicability of Ingress Filtering  . . . . . .  8
       3.1 Ingress Filtering at Multiple Levels . . . . . . . . . . .  8
       3.2 Ingress Filtering to Protect Your Own Infrastructure . . .  8
       3.3 Ingress Filtering on Peering Links . . . . . . . . . . . .  9
   4.  Solutions to Ingress Filtering with Multihoming  . . . . . . .  9
       4.1 Use Loose RPF When Appropriate . . . . . . . . . . . . . . 10
       4.2 Ensure That Each ISP's Ingress Filter Is Complete  . . . . 11
       4.3 Send Traffic Using a Provider Prefix Only to That Provider 11
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   6.  Conclusions and Future Work  . . . . . . . . . . . . . . . . . 13
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
       8.1.  Normative References . . . . . . . . . . . . . . . . . . 14
       8.2.  Informative References . . . . . . . . . . . . . . . . . 14
   9.  Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 15
   10. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 16


























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