Re: [GROW] Genart telechat review of draft-ietf-grow-bgp-reject-07

Job Snijders <job@xxxxxxx> · Mon, 22 May 2017 13:04:48 +0200

Dear Dale,

Thank you for your time reviewing this document.

On Fri, May 19, 2017 at 11:19:34AM -0700, Dale Worley wrote:
> Summary:  This draft is basically ready for publication, but has nits
> that should be fixed before publication.
> 
>    1. Introduction
> 			
>    BGP routing security issues need to be addressed in order to make
>    the Internet more stable.  Route leaks [RFC7908] are part of the
>    problem, but software defects or operator misconfiguration can
>    contribute too.  This document updates [RFC4271] in order to
>    improve the default level of Internet routing security.
> 
> This paragraph is a good introduction, but it isn't very cohesive.  I
> suggest revising the third sentence to something like:
> 
>    This document updates [RFC4271] so that routes are neither imported
>    nor exported unless specifically enabled by configuration, thus
>    reducing route leaks, and so improving the default level of
>    Internet routing security.
> 
> Then again, considering section 5 paragraph 1, perhaps this update
> reduces all three causes (route leaks, software defects, and operator
> misconfigurations), in which case you could say
> 
>    This document updates [RFC4271] so that routes are neither imported
>    nor exported unless specifically enabled by configuration, thus
>    reducing the consequences of these problems, and so improving the
>    default level of Internet routing security.

I've accepted the latter suggestion.

> --
> 
>    BGP speakers following this specification do not use or send routes
>    on EBGP sessions, unless configured to do otherwise.
> 
> This sentence seems to be correct as written, but somehow it reads
> awkwardly to me.  I think the problem is that "do otherwise" is used,
> when the "otherwise" is "do not use ...".  I think it would read more
> smoothly to say:
> 
>    BGP speakers following this specification do not use or send routes
>    on EBGP sessions, unless specifically configured to do so.
> 
> Perhaps the Editor should be consulted about this.

I've accepted this suggestion.

> --
> 
>    2.  Terminology
> 
>    [RFC4271] describes a Policy Information Base (PIB) which contains
>    local policies that can be applied to the information in the
>    Routing Information Base (RIB).  This document distinguishes the
>    type of policy based on its application.
> 
> Here, you want to say "the type of a policy" or "the type of a
> particular policy", because "policy" refers to a specific policy
> within a set of policies, rather than being a mass noun.

accepted.

> 
>    3. Changes to RFC4271	
> 				
>    This section describes the Updates to [RFC4271] that define the
>    default behavior of a BGP speaker when there are no Import or
>    Export Policies associated with a particular EBGP session.
> 
> Of course, there is no need to capitalize "Updates".
> 
> The wording "describes the updates" is awkward.  Really, it lists or
> specifies the updates, rather than describing them.  Also, the use of
> "updates ... that ..." suggests that there is a larger set of updates
> from which "the updates that define the default behavior" are
> selected, and that smaller set will be described in this section.
> Instead, there are updates, and those updates define the default
> behavior.
> 
> So I think a better wording is:
> 
>    This section updates [RFC4271] to change the default behavior ...".
> 
> It's probably worth consulting the Edtior to see if a better wording
> is possible.

I suggest: "This section updates <xref target="RFC4271" /> to specify
the default behavior of a BGP speaker when there are no Import or Export
Policies associated with a particular EBGP session."

> --
> 
>    The following paragraph is added to Section 9.1 (Decision Process)
>    after the fifth paragraph ending in "route aggregation and route
>    information reduction":
> 
> Strictly, this says that there are five paragraphs which end in "route
> aggregation and route information reduction", and the fifth of them is
> being discussed.  The correct wording is 'the fifth paragraph, which
> ends in "route aggregation and route information reduction"'.

accepted.

>    The following paragraph is added to Section 9.1.3 (Phase 3: Route
>    Dissemination) after the third paragraph ending in "by means of an
>    UPDATE message (see 9.2).":
> 
> Similarly, this should be 'the third paragraph, which ends in "by
> means of an UPDATE message (see 9.2)."'

accepted.

>    5. Security Considerations	
> 
>    Permissive default routing policies can result in inadvertent
>    effects such as route leaks [RFC7908], in general resulting in
>    rerouting of traffic through an unexpected path.
> 
> The word "rerouting" emphasizes that the traffic's route has been
> changed, whereas I think the problem you are concerned with is simply
> that the traffic is routed through an unexpected path.  That suggests
> changing "rerouting" to "routing".
> 
> Then again, perhaps routing people always conceptualize an incorrect
> route as a change from an expected or correct route, in which case
> "rerouting" is the best word to use.

"routing" is perfectly fine too in this context since we are explicit
about "unexpected paths". Accepted.

>    Appendix A.  Transition Considerations
> 
>    It is anticipated that transitioning to a compliant BGP
>    implementation will require a process thay may take several years.
> 
> You probably want to s/a compliant BGP implementation/compliant BGP
> implementations/, unless you are describing the process for an
> individual operator, not for all operators collectively.

The process refers to the vendors of BGP implementations, not operators.
Given that the appendix is targetted mostly to the vendor audience,
would you have a suggestion within that context?

>    A.1. N+1 N+2 Release Strategy	
> 
>    An implementer could leverage an approach described as "the N+1 and
>    N+2 release strategy".
> 
> I prefer reducing the words within the quotation marks.  (But probably
> it's best to ask the Editor.)  That would give:
> 
>    An implementer could leverage an approach described as the "N+1 and
>    N+2" release strategy.
> 
> The section title is difficult to understand without context.  I
> suggest revising it in a way that parallels the way you use the term
> in the text of the section, such as:
> 
>    A.1. Using an "N+1 and N+2" Release Strategy	
> 
> This conveys the maximum possible amount of information to a reader
> (like me) who doesn't know what the "N+1 and N+2" strategy is, namely
> that there is a known release strategy with the name "N+1 and N+2",
> and that the section describes how to use it in this context (and
> hopefully, defines it as well). -- (All of which expectations are
> met.)

I moved the quotation marks around according to your suggestions.

>    "ebgp insecure-mode"
> 
> I think that in this phrase, "ebgp insecure" modifies "mode", and so
> it would be written "ebgp-insecure mode".  (As opposed to "ebgp"
> modifying "insecure mode", in which case it would indeed be written
> "ebgp insecure-mode".)

The current phrasing aligns with industry standards (for better of for
worse), one should consider the suggestion arbitrary, it is merely a
configuration keyword suggestion and not normative. 

I've attached a -07 -> -08 htmldiff which incorporates your suggestions.
After we covered the 's/a compliant BGP implementation/compliant BGP
implementations/' subtopic, and my co-authors reviewed the proposed
changes, we can proceed to cut & publish a -08.

Kind regards,

Job
Title: Diff: draft-ietf-grow-bgp-reject-07.txt - draft-ietf-grow-bgp-reject-08.txt

   draft-ietf-grow-bgp-reject-07.txt    draft-ietf-grow-bgp-reject-08.txt   

      Global Routing Operations                                       J. Mauch  Global Routing Operations                                       J. Mauch 
      Internet-Draft                                                    Akamai  Internet-Draft                                                    Akamai 
      Updates: 4271 (if approved)                                  J. Snijders  Updates: 4271 (if approved)                                  J. Snijders 
      Intended status: Standards Track                                     NTT  Intended status: Standards Track                                     NTT 

      Expires: November 9, 2017                                     G. Hankins  Expires: November 23, 2017                                    G. Hankins 
                                                                         Nokia                                                                     Nokia 

                                                                   May 8, 2017                                                              May 22, 2017 

              Default EBGP Route Propagation Behavior Without Policies          Default EBGP Route Propagation Behavior Without Policies 

                           draft-ietf-grow-bgp-reject-07                       draft-ietf-grow-bgp-reject-08 

      Abstract  Abstract 

         This document updates RFC4271 by defining the default behavior of a     This document updates RFC4271 by defining the default behavior of a 
         BGP speaker when there is no Import or Export Policy associated with     BGP speaker when there is no Import or Export Policy associated with 
         an External BGP session.     an External BGP session. 

      Requirements Language  Requirements Language 

         The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",     The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 

      skipping to change at page 1, line 41  skipping to change at page 1, line 41 
         Internet-Drafts are working documents of the Internet Engineering     Internet-Drafts are working documents of the Internet Engineering 
         Task Force (IETF).  Note that other groups may also distribute     Task Force (IETF).  Note that other groups may also distribute 
         working documents as Internet-Drafts.  The list of current Internet-     working documents as Internet-Drafts.  The list of current Internet- 
         Drafts is at http://datatracker.ietf.org/drafts/current/.     Drafts is at http://datatracker.ietf.org/drafts/current/. 

         Internet-Drafts are draft documents valid for a maximum of six months     Internet-Drafts are draft documents valid for a maximum of six months 
         and may be updated, replaced, or obsoleted by other documents at any     and may be updated, replaced, or obsoleted by other documents at any 
         time.  It is inappropriate to use Internet-Drafts as reference     time.  It is inappropriate to use Internet-Drafts as reference 
         material or to cite them other than as "work in progress."     material or to cite them other than as "work in progress." 

         This Internet-Draft will expire on November 9, 2017.     This Internet-Draft will expire on November 23, 2017. 

      Copyright Notice  Copyright Notice 

         Copyright (c) 2017 IETF Trust and the persons identified as the     Copyright (c) 2017 IETF Trust and the persons identified as the 
         document authors.  All rights reserved.     document authors.  All rights reserved. 

         This document is subject to BCP 78 and the IETF Trust's Legal     This document is subject to BCP 78 and the IETF Trust's Legal 
         Provisions Relating to IETF Documents     Provisions Relating to IETF Documents 
         (http://trustee.ietf.org/license-info) in effect on the date of     (http://trustee.ietf.org/license-info) in effect on the date of 
         publication of this document.  Please review these documents     publication of this document.  Please review these documents 

      skipping to change at page 2, line 25  skipping to change at page 2, line 25 
         2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3     2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3 
         3.  Changes to RFC4271  . . . . . . . . . . . . . . . . . . . . .   3     3.  Changes to RFC4271  . . . . . . . . . . . . . . . . . . . . .   3 
         4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4     4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4 
         5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4     5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4 
         6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4     6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4 
         7.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   4     7.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   4 
         8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5     8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5 
           8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5       8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5 
           8.2.  Informative References  . . . . . . . . . . . . . . . . .   5       8.2.  Informative References  . . . . . . . . . . . . . . . . .   5 
         Appendix A.  Transition Considerations  . . . . . . . . . . . . .   5     Appendix A.  Transition Considerations  . . . . . . . . . . . . .   5 

           A.1.  N+1 N+2 Release Strategy  . . . . . . . . . . . . . . . .   5       A.1.  "N+1 N+2" Release Strategy  . . . . . . . . . . . . . . .   5 
         Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6     Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6 

      1.  Introduction  1.  Introduction 

         BGP routing security issues need to be addressed in order to make the     BGP routing security issues need to be addressed in order to make the 
         Internet more stable.  Route leaks [RFC7908] are part of the problem,     Internet more stable.  Route leaks [RFC7908] are part of the problem, 
         but software defects or operator misconfiguration can contribute too.     but software defects or operator misconfiguration can contribute too. 

         This document updates [RFC4271] in order to improve the default level     This document updates [RFC4271] so that routes are neither imported 
         of Internet routing security.     nor exported unless specifically enabled by configuration, thus 
          reducing the consequences of these problems, and so improving the 
          default level of Internet routing security. 

         Many deployed BGP speakers send and accept any and all route     Many deployed BGP speakers send and accept any and all route 
         announcements between their BGP neighbors by default.  This practice     announcements between their BGP neighbors by default.  This practice 
         dates back to the early days of the Internet, where operators were     dates back to the early days of the Internet, where operators were 
         permissive in sending routing information to allow all networks to     permissive in sending routing information to allow all networks to 
         reach each other.  As the Internet has become more densely     reach each other.  As the Internet has become more densely 
         interconnected, the risk of a misbehaving BGP speaker poses     interconnected, the risk of a misbehaving BGP speaker poses 
         significant risks to Internet routing.     significant risks to Internet routing. 

         This specification intends to improve this situation by requiring the     This specification intends to improve this situation by requiring the 
         explicit configuration of both BGP Import and Export Policies for any     explicit configuration of both BGP Import and Export Policies for any 
         External BGP (EBGP) session such as customers, peers, or     External BGP (EBGP) session such as customers, peers, or 
         confederation boundaries for all enabled address families.  Through     confederation boundaries for all enabled address families.  Through 
         codification of the aforementioned requirement, operators will     codification of the aforementioned requirement, operators will 
         benefit from consistent behaviour across different BGP     benefit from consistent behaviour across different BGP 
         implementations.     implementations. 

         BGP speakers following this specification do not use or send routes     BGP speakers following this specification do not use or send routes 

         on EBGP sessions, unless configured to do otherwise.     on EBGP sessions, unless specifically configured to do so. 

      2.  Terminology  2.  Terminology 

         [RFC4271] describes a Policy Information Base (PIB) which contains     [RFC4271] describes a Policy Information Base (PIB) which contains 
         local policies that can be applied to the information in the Routing     local policies that can be applied to the information in the Routing 

         Information Base (RIB).  This document distinguishes the type of     Information Base (RIB).  This document distinguishes the type of a 
         policy based on its application.     policy based on its application. 

         Import Policy: a local policy to be applied to the information     Import Policy: a local policy to be applied to the information 
         contained in the Adj-RIBs-In.  As described in Section 3.2 [RFC4271],     contained in the Adj-RIBs-In.  As described in Section 3.2 [RFC4271], 
         the Adj-RIBs-In contain information learned from other BGP speakers,     the Adj-RIBs-In contain information learned from other BGP speakers, 
         and the application of the Import Policy results in the routes that     and the application of the Import Policy results in the routes that 
         will be considered in the Decision Process by the local BGP speaker.     will be considered in the Decision Process by the local BGP speaker. 

         Export Policy: a local policy to be applied in selecting the     Export Policy: a local policy to be applied in selecting the 
         information contained in the Adj-RIBs-Out.  As described in     information contained in the Adj-RIBs-Out.  As described in 
         Section 3.2 [RFC4271], the Adj-RIBs-Out contain information that has     Section 3.2 [RFC4271], the Adj-RIBs-Out contain information that has 
         been selected for advertisement to other BGP speakers.     been selected for advertisement to other BGP speakers. 

      3.  Changes to RFC4271  3.  Changes to RFC4271 

         This section describes the Updates to [RFC4271] that define the     This section updates [RFC4271] to specify the default behavior of a 
         default behavior of a BGP speaker when there are no Import or Export     BGP speaker when there are no Import or Export Policies associated 
         Policies associated with a particular EBGP session.  A BGP speaker     with a particular EBGP session.  A BGP speaker MAY provide a 
         MAY provide a configuration option to deviate from the following     configuration option to deviate from the following updated behaviors. 
         updated behaviors.  

         The following paragraph is added to Section 9.1 (Decision Process)     The following paragraph is added to Section 9.1 (Decision Process) 

         after the fifth paragraph ending in "route aggregation and route     after the fifth paragraph, which ends in "route aggregation and route 
         information reduction":     information reduction": 

            Routes contained in an Adj-RIB-In associated with an EBGP peer        Routes contained in an Adj-RIB-In associated with an EBGP peer 
            SHALL NOT be considered eligible in the Decision Process if no        SHALL NOT be considered eligible in the Decision Process if no 
            explicit Import Policy has been applied.        explicit Import Policy has been applied. 

         The following paragraph is added to Section 9.1.3 (Phase 3: Route     The following paragraph is added to Section 9.1.3 (Phase 3: Route 

         Dissemination) after the third paragraph ending in "by means of an     Dissemination) after the third paragraph, which ends in "by means of 
         UPDATE message (see 9.2).":     an UPDATE message (see 9.2).": 

            Routes SHALL NOT be added to an Adj-RIB-Out associated with an        Routes SHALL NOT be added to an Adj-RIB-Out associated with an 
            EBGP peer if no explicit Export Policy has been applied.        EBGP peer if no explicit Export Policy has been applied. 

      4.  Acknowledgments  4.  Acknowledgments 

         The authors would like to thank the following people for their     The authors would like to thank the following people for their 
         comments, support and review: Shane Amante, Christopher Morrow,     comments, support and review: Shane Amante, Christopher Morrow, 
         Robert Raszuk, Greg Skinner, Adam Chappell, Sriram Kotikalapudi,     Robert Raszuk, Greg Skinner, Adam Chappell, Sriram Kotikalapudi, 
         Brian Dickson, Jeffrey Haas, John Heasley, Ignas Bagdonas, Donald     Brian Dickson, Jeffrey Haas, John Heasley, Ignas Bagdonas, Donald 

         Smith, Dale Worley, Alvaro Retana, and John Scudder.     Smith, Dale Worley, Alvaro Retana, John Scudder, and Dale Worley. 

      5.  Security Considerations  5.  Security Considerations 

         Permissive default routing policies can result in inadvertent effects     Permissive default routing policies can result in inadvertent effects 

         such as route leaks [RFC7908], in general resulting in rerouting of     such as route leaks [RFC7908], in general resulting in routing of 
         traffic through an unexpected path.  While it is possible for an     traffic through an unexpected path.  While it is possible for an 
         operator to use monitoring to detect unexpected flows, there is no     operator to use monitoring to detect unexpected flows, there is no 
         general framework that can be applied.  These policies also have the     general framework that can be applied.  These policies also have the 
         potential to expose software defects or misconfiguration that could     potential to expose software defects or misconfiguration that could 
         have unforeseen technical and business impacting effects.     have unforeseen technical and business impacting effects. 

         The update to [RFC4271] specified in this document is intended to     The update to [RFC4271] specified in this document is intended to 
         eliminate those inadvertent effects.  Operators must explicitly     eliminate those inadvertent effects.  Operators must explicitly 
         configure Import and Export Policies to achieve their expected goals.     configure Import and Export Policies to achieve their expected goals. 
         There is of course no protection against a malicious or incorrect     There is of course no protection against a malicious or incorrect 

      skipping to change at page 5, line 41  skipping to change at page 5, line 41 

         This appendix is non-normative.     This appendix is non-normative. 

         It is anticipated that transitioning to a compliant BGP     It is anticipated that transitioning to a compliant BGP 
         implementation will require a process thay may take several years.     implementation will require a process thay may take several years. 

         It is understood and acknowledged that operators who are taking     It is understood and acknowledged that operators who are taking 
         advantage of an undefined behavior will always be surprised by     advantage of an undefined behavior will always be surprised by 
         changes to said behavior.     changes to said behavior. 

      A.1.  N+1 N+2 Release Strategy  A.1.  "N+1 N+2" Release Strategy 

         An implementer could leverage an approach described as "the N+1 and     An implementer could leverage an approach described as the "N+1 and 
         N+2 release strategy".  In release N+1, the implementer introduces a     N+2" release strategy.  In release N+1, the implementer introduces a 
         new default configuration parameter to indicate that the BGP speaker     new default configuration parameter to indicate that the BGP speaker 
         is operating in "ebgp insecure-mode".  In addition to the     is operating in "ebgp insecure-mode".  In addition to the 
         introduction of the new parameter, an implementer could begin to     introduction of the new parameter, an implementer could begin to 
         display informational warnings to the operator that certain parts of     display informational warnings to the operator that certain parts of 
         the configuration are incomplete.  In release N+1, operators of the     the configuration are incomplete.  In release N+1, operators of the 
         BGP implementation become aware that a configurable default exists in     BGP implementation become aware that a configurable default exists in 
         the implementation, and can prepare accordingly.  In release N+2 or     the implementation, and can prepare accordingly.  In release N+2 or 
         later, the inverse of the previous default configuration parameter     later, the inverse of the previous default configuration parameter 
         that was introduced in release N+1 becomes the new default.     that was introduced in release N+1 becomes the new default. 

      End of changes. 15 change blocks. 
     22 lines changed or deleted  23 lines changed or added 

This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/ 

	draft-ietf-grow-bgp-reject-07.txt	draft-ietf-grow-bgp-reject-08.txt

	Global Routing Operations J. Mauch	Global Routing Operations J. Mauch
	Internet-Draft Akamai	Internet-Draft Akamai
	Updates: 4271 (if approved) J. Snijders	Updates: 4271 (if approved) J. Snijders
	Intended status: Standards Track NTT	Intended status: Standards Track NTT

	Expires: November 9, 2017 G. Hankins	Expires: November 23, 2017 G. Hankins
	Nokia	Nokia

	May 8, 2017	May 22, 2017

	Default EBGP Route Propagation Behavior Without Policies	Default EBGP Route Propagation Behavior Without Policies

	draft-ietf-grow-bgp-reject-07	draft-ietf-grow-bgp-reject-08

	Abstract	Abstract

	This document updates RFC4271 by defining the default behavior of a	This document updates RFC4271 by defining the default behavior of a
	BGP speaker when there is no Import or Export Policy associated with	BGP speaker when there is no Import or Export Policy associated with
	an External BGP session.	an External BGP session.

	Requirements Language	Requirements Language

	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",

	skipping to change at page 1, line 41	skipping to change at page 1, line 41
	Internet-Drafts are working documents of the Internet Engineering	Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute	Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-	working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.	Drafts is at http://datatracker.ietf.org/drafts/current/.

	Internet-Drafts are draft documents valid for a maximum of six months	Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any	and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference	time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."	material or to cite them other than as "work in progress."


	This Internet-Draft will expire on November 9, 2017.	This Internet-Draft will expire on November 23, 2017.

	Copyright Notice	Copyright Notice

	Copyright (c) 2017 IETF Trust and the persons identified as the	Copyright (c) 2017 IETF Trust and the persons identified as the
	document authors. All rights reserved.	document authors. All rights reserved.

	This document is subject to BCP 78 and the IETF Trust's Legal	This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents	Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of	(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents	publication of this document. Please review these documents

	skipping to change at page 2, line 25	skipping to change at page 2, line 25
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Changes to RFC4271 . . . . . . . . . . . . . . . . . . . . . 3	3. Changes to RFC4271 . . . . . . . . . . . . . . . . . . . . . 3
	4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4	4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 4	5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
	7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4	7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	8.1. Normative References . . . . . . . . . . . . . . . . . . 5	8.1. Normative References . . . . . . . . . . . . . . . . . . 5
	8.2. Informative References . . . . . . . . . . . . . . . . . 5	8.2. Informative References . . . . . . . . . . . . . . . . . 5
	Appendix A. Transition Considerations . . . . . . . . . . . . . 5	Appendix A. Transition Considerations . . . . . . . . . . . . . 5

	A.1. N+1 N+2 Release Strategy . . . . . . . . . . . . . . . . 5	A.1. "N+1 N+2" Release Strategy . . . . . . . . . . . . . . . 5
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6

	1. Introduction	1. Introduction

	BGP routing security issues need to be addressed in order to make the	BGP routing security issues need to be addressed in order to make the
	Internet more stable. Route leaks [RFC7908] are part of the problem,	Internet more stable. Route leaks [RFC7908] are part of the problem,
	but software defects or operator misconfiguration can contribute too.	but software defects or operator misconfiguration can contribute too.

	This document updates [RFC4271] in order to improve the default level	This document updates [RFC4271] so that routes are neither imported
	of Internet routing security.	nor exported unless specifically enabled by configuration, thus
		reducing the consequences of these problems, and so improving the
		default level of Internet routing security.

	Many deployed BGP speakers send and accept any and all route	Many deployed BGP speakers send and accept any and all route
	announcements between their BGP neighbors by default. This practice	announcements between their BGP neighbors by default. This practice
	dates back to the early days of the Internet, where operators were	dates back to the early days of the Internet, where operators were
	permissive in sending routing information to allow all networks to	permissive in sending routing information to allow all networks to
	reach each other. As the Internet has become more densely	reach each other. As the Internet has become more densely
	interconnected, the risk of a misbehaving BGP speaker poses	interconnected, the risk of a misbehaving BGP speaker poses
	significant risks to Internet routing.	significant risks to Internet routing.

	This specification intends to improve this situation by requiring the	This specification intends to improve this situation by requiring the
	explicit configuration of both BGP Import and Export Policies for any	explicit configuration of both BGP Import and Export Policies for any
	External BGP (EBGP) session such as customers, peers, or	External BGP (EBGP) session such as customers, peers, or
	confederation boundaries for all enabled address families. Through	confederation boundaries for all enabled address families. Through
	codification of the aforementioned requirement, operators will	codification of the aforementioned requirement, operators will
	benefit from consistent behaviour across different BGP	benefit from consistent behaviour across different BGP
	implementations.	implementations.

	BGP speakers following this specification do not use or send routes	BGP speakers following this specification do not use or send routes

	on EBGP sessions, unless configured to do otherwise.	on EBGP sessions, unless specifically configured to do so.

	2. Terminology	2. Terminology

	[RFC4271] describes a Policy Information Base (PIB) which contains	[RFC4271] describes a Policy Information Base (PIB) which contains
	local policies that can be applied to the information in the Routing	local policies that can be applied to the information in the Routing

	Information Base (RIB). This document distinguishes the type of	Information Base (RIB). This document distinguishes the type of a
	policy based on its application.	policy based on its application.

	Import Policy: a local policy to be applied to the information	Import Policy: a local policy to be applied to the information
	contained in the Adj-RIBs-In. As described in Section 3.2 [RFC4271],	contained in the Adj-RIBs-In. As described in Section 3.2 [RFC4271],
	the Adj-RIBs-In contain information learned from other BGP speakers,	the Adj-RIBs-In contain information learned from other BGP speakers,
	and the application of the Import Policy results in the routes that	and the application of the Import Policy results in the routes that
	will be considered in the Decision Process by the local BGP speaker.	will be considered in the Decision Process by the local BGP speaker.

	Export Policy: a local policy to be applied in selecting the	Export Policy: a local policy to be applied in selecting the
	information contained in the Adj-RIBs-Out. As described in	information contained in the Adj-RIBs-Out. As described in
	Section 3.2 [RFC4271], the Adj-RIBs-Out contain information that has	Section 3.2 [RFC4271], the Adj-RIBs-Out contain information that has
	been selected for advertisement to other BGP speakers.	been selected for advertisement to other BGP speakers.

	3. Changes to RFC4271	3. Changes to RFC4271


	This section describes the Updates to [RFC4271] that define the	This section updates [RFC4271] to specify the default behavior of a
	default behavior of a BGP speaker when there are no Import or Export	BGP speaker when there are no Import or Export Policies associated
	Policies associated with a particular EBGP session. A BGP speaker	with a particular EBGP session. A BGP speaker MAY provide a
	MAY provide a configuration option to deviate from the following	configuration option to deviate from the following updated behaviors.
	updated behaviors.

	The following paragraph is added to Section 9.1 (Decision Process)	The following paragraph is added to Section 9.1 (Decision Process)

	after the fifth paragraph ending in "route aggregation and route	after the fifth paragraph, which ends in "route aggregation and route
	information reduction":	information reduction":

	Routes contained in an Adj-RIB-In associated with an EBGP peer	Routes contained in an Adj-RIB-In associated with an EBGP peer
	SHALL NOT be considered eligible in the Decision Process if no	SHALL NOT be considered eligible in the Decision Process if no
	explicit Import Policy has been applied.	explicit Import Policy has been applied.

	The following paragraph is added to Section 9.1.3 (Phase 3: Route	The following paragraph is added to Section 9.1.3 (Phase 3: Route

	Dissemination) after the third paragraph ending in "by means of an	Dissemination) after the third paragraph, which ends in "by means of
	UPDATE message (see 9.2).":	an UPDATE message (see 9.2).":

	Routes SHALL NOT be added to an Adj-RIB-Out associated with an	Routes SHALL NOT be added to an Adj-RIB-Out associated with an
	EBGP peer if no explicit Export Policy has been applied.	EBGP peer if no explicit Export Policy has been applied.

	4. Acknowledgments	4. Acknowledgments

	The authors would like to thank the following people for their	The authors would like to thank the following people for their
	comments, support and review: Shane Amante, Christopher Morrow,	comments, support and review: Shane Amante, Christopher Morrow,
	Robert Raszuk, Greg Skinner, Adam Chappell, Sriram Kotikalapudi,	Robert Raszuk, Greg Skinner, Adam Chappell, Sriram Kotikalapudi,
	Brian Dickson, Jeffrey Haas, John Heasley, Ignas Bagdonas, Donald	Brian Dickson, Jeffrey Haas, John Heasley, Ignas Bagdonas, Donald

	Smith, Dale Worley, Alvaro Retana, and John Scudder.	Smith, Dale Worley, Alvaro Retana, John Scudder, and Dale Worley.

	5. Security Considerations	5. Security Considerations

	Permissive default routing policies can result in inadvertent effects	Permissive default routing policies can result in inadvertent effects

	such as route leaks [RFC7908], in general resulting in rerouting of	such as route leaks [RFC7908], in general resulting in routing of
	traffic through an unexpected path. While it is possible for an	traffic through an unexpected path. While it is possible for an
	operator to use monitoring to detect unexpected flows, there is no	operator to use monitoring to detect unexpected flows, there is no
	general framework that can be applied. These policies also have the	general framework that can be applied. These policies also have the
	potential to expose software defects or misconfiguration that could	potential to expose software defects or misconfiguration that could
	have unforeseen technical and business impacting effects.	have unforeseen technical and business impacting effects.

	The update to [RFC4271] specified in this document is intended to	The update to [RFC4271] specified in this document is intended to
	eliminate those inadvertent effects. Operators must explicitly	eliminate those inadvertent effects. Operators must explicitly
	configure Import and Export Policies to achieve their expected goals.	configure Import and Export Policies to achieve their expected goals.
	There is of course no protection against a malicious or incorrect	There is of course no protection against a malicious or incorrect

	skipping to change at page 5, line 41	skipping to change at page 5, line 41

	This appendix is non-normative.	This appendix is non-normative.

	It is anticipated that transitioning to a compliant BGP	It is anticipated that transitioning to a compliant BGP
	implementation will require a process thay may take several years.	implementation will require a process thay may take several years.

	It is understood and acknowledged that operators who are taking	It is understood and acknowledged that operators who are taking
	advantage of an undefined behavior will always be surprised by	advantage of an undefined behavior will always be surprised by
	changes to said behavior.	changes to said behavior.


	A.1. N+1 N+2 Release Strategy	A.1. "N+1 N+2" Release Strategy


	An implementer could leverage an approach described as "the N+1 and	An implementer could leverage an approach described as the "N+1 and
	N+2 release strategy". In release N+1, the implementer introduces a	N+2" release strategy. In release N+1, the implementer introduces a
	new default configuration parameter to indicate that the BGP speaker	new default configuration parameter to indicate that the BGP speaker
	is operating in "ebgp insecure-mode". In addition to the	is operating in "ebgp insecure-mode". In addition to the
	introduction of the new parameter, an implementer could begin to	introduction of the new parameter, an implementer could begin to
	display informational warnings to the operator that certain parts of	display informational warnings to the operator that certain parts of
	the configuration are incomplete. In release N+1, operators of the	the configuration are incomplete. In release N+1, operators of the
	BGP implementation become aware that a configurable default exists in	BGP implementation become aware that a configurable default exists in
	the implementation, and can prepare accordingly. In release N+2 or	the implementation, and can prepare accordingly. In release N+2 or
	later, the inverse of the previous default configuration parameter	later, the inverse of the previous default configuration parameter
	that was introduced in release N+1 becomes the new default.	that was introduced in release N+1 becomes the new default.


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