PROBE: A Utility for Probing Interfaces
RFC 8335

Received changes through RFC Editor sync (created alias RFC 8335, changed title to 'PROBE: A Utility for Probing Interfaces', changed abstract to 'This document describes a network diagnostic tool called PROBE.  PROBE is similar to PING in that it can be used to query the status of a probed interface, but it differs from PING in that it does not require bidirectional connectivity between the probing and probed interfaces.  Instead, PROBE requires bidirectional connectivity between the probing interface and a proxy interface.  The proxy interface can reside on the same node as the probed interface, or it can reside on a node to which the probed interface is directly connected.  This document updates RFC 4884.', changed pages to 19, changed standardization level to Proposed Standard, changed state to RFC, added RFC published event at 2018-02-22, changed IESG state to RFC Published, created updates relation between draft-ietf-intarea-probe and RFC 4884)

[Ballot comment]
In the version I'd initially reviewed there were codes for things like: "E (Ethernet) - The E-bit is set if the A-bit is also set and IPv4 is running on the probed interface.  Otherwise, the E-bit is clear."
I was going to fuss and ask what makes Ethernet special -- but, seeing as this is removed in the newest version I have nothing to fuss about. :-)

The below was originally a DISCUSS, changed to NoObj -- but wanted it noted:
This is, I believe a minor DISCUSS, and I'll happily clear it once a commitment is made that it will be addressed / on the call (AKA, I'm not going to hold up the document, but there isn't a "Comment" and "Very important comment" in the datatracker).

Stefan Winter's OpsDir review contains:
"* Introduction
states "[...] if it appears in the IPv4 Address Resolution Protocol (ARP) table [RFC0826] or IPv6 Neighbor Cache [RFC4861]." "Appears" is a rather loose word, as entries in those tables can have multiple states. E.g. for IPv6, which of the states DELAY, STALE, REACHABLE do you mean? All? Or only a subset? In IPv4, do you mean the "C" flag exclusively?
Also, when the proxy operates remotely (i.e. bases the reply on ARP/Neighbor Cache rather than ifOperStatus), does it actively ping the interface in question itself? If not, how does it handle an interface address which is not in the ARP/Neighbour table simply because the entry has timed out? The interface might be up and active nontheless. In such a case, reporting "does not exist" is false."

Ron Bonica's suggested solution in: https://www.ietf.org/mail-archive/web/int-area/current/msg06136.html works for me, but I do not see it in the version being discussed. This would make a substantive change to the document, I wanted to draw attention to it.

[Ballot comment]
No objection to the publication of this document. However, some comments.

So basically you specify the same functionality as remote ping MIB in RFC4560 where
- probing interface = SNMP manager
- proxy interface = SNMP agent
- probed agent = destination
Right? So any connection with RFC4560?

I guess this mechanism is a similar functionality as RFC 6812, where
- proxy agent = sender
- responder = destination
... even the technology is not based on the ICMP extended echo
As such I believe that the RFC 6812 IPR applies here as well.
However, I'm not the one to make the call. So I will forward to the appropriate persons.

Potentially the OWAMP IPRs apply as well.
https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-ippm-owdp

[Ballot comment]
I just had a very brief read of this document, but otherwise I'm missing something, I believe the bit lengths of the fields of the Interface Identification Object are not specified. Is there maybe an image missing?

[Ballot comment]
-1.2: There is at least one lower case MUST. Unless that is intended as normative, please consider using the boilerplate from RFC8174.

-8, last paragraph: "MUST NOT leak information" seems more like a goal or a statement of fact than a normative requirement. (I think the 2nd MUST in that paragraph describes the real normative requirement")

[Ballot discuss]
This is, I believe a minor DISCUSS, and I'll happily clear it once a commitment is made that it will be addressed / on the call (AKA, I'm not going to hold up the document, but there isn't a "Comment" and "Very important comment" in the datatracker).

Stefan Winter's OpsDir review contains:
"* Introduction
states "[...] if it appears in the IPv4 Address Resolution Protocol (ARP) table [RFC0826] or IPv6 Neighbor Cache [RFC4861]." "Appears" is a rather loose word, as entries in those tables can have multiple states. E.g. for IPv6, which of the states DELAY, STALE, REACHABLE do you mean? All? Or only a subset? In IPv4, do you mean the "C" flag exclusively?
Also, when the proxy operates remotely (i.e. bases the reply on ARP/Neighbor Cache rather than ifOperStatus), does it actively ping the interface in question itself? If not, how does it handle an interface address which is not in the ARP/Neighbour table simply because the entry has timed out? The interface might be up and active nontheless. In such a case, reporting "does not exist" is false."

Ron Bonica's suggested solution in: https://www.ietf.org/mail-archive/web/int-area/current/msg06136.html works for me, but I do not see it in the version being discussed. This would make a substantive change to the document, I wanted to draw attention to it.

[Ballot discuss]
This is, I believe a minor DISCUSS, and I'll happily clear it once a commitment is made that it will be addressed (AKA, I'm not going to hold up the document, but there isn't a "Comment" and "Very important comment" in the datatracker).

Stefan Winter's OpsDir review contains:
"* Introduction
states "[...] if it appears in the IPv4 Address Resolution Protocol (ARP) table [RFC0826] or IPv6 Neighbor Cache [RFC4861]." "Appears" is a rather loose word, as entries in those tables can have multiple states. E.g. for IPv6, which of the states DELAY, STALE, REACHABLE do you mean? All? Or only a subset? In IPv4, do you mean the "C" flag exclusively?
Also, when the proxy operates remotely (i.e. bases the reply on ARP/Neighbor Cache rather than ifOperStatus), does it actively ping the interface in question itself? If not, how does it handle an interface address which is not in the ARP/Neighbour table simply because the entry has timed out? The interface might be up and active nontheless. In such a case, reporting "does not exist" is false."

Ron Bonica's suggested solution in: https://www.ietf.org/mail-archive/web/int-area/current/msg06136.html works for me, but I do not see it in the version being discussed. This would make a substantive change to the document, I wanted to draw attention to it.

[Ballot comment]
In the version I'd initially reviewed there were codes for things like: "E (Ethernet) - The E-bit is set if the A-bit is also set and IPv4 is running on the probed interface.  Otherwise, the E-bit is clear."
I was going to fuss and ask what makes Ethernet special -- but, seeing as this is removed in the newest version I have nothing to fuss about. :-)

[Ballot comment]
(1) The Code field of the Request is set to 0 - what happens if a different value is received?

(2) The Request includes 2 fields (Identifier and Sequence Number) that are used “to aid in matching Extended Echo Replies to Extended Echo Requests”.  Their use seems to be a local matter (as the values are simply copied in to the Reply.  Can you please provide guidance on their use?  Why are there 2 fields (and not just a single one)?  I’m assuming/hoping that the design had use cases in mind that can be reflected in the document.

(3) It would be nice to set up a registry for the Reserved fields.

(4) I’m not sure I understand the use/intention of the L-bit.  The description says that it is used (on the Request) to indicate whether the probed interfaces resides on the proxy node (or not).  How does the originator of the Request know that information?  The other function of this bit seems to be to control how the Interface Identification Object can identify the probed interface…while it seems to make sense that a probed interface that doesn’t reside on the proxy node would only be identified by it’s address, it still makes me wonder how the sender of the Request would know, and why it even matters that it does and that it indicates it to the proxy node.

[Ballot comment]
Thanks for your responses on the SecDir review. 

There were 3 points and I think you've come to a conclusion on each of them, but let me verify from the updated text in versions 8 and 9.

From the review:
* The probed interface can be identified by an IEEE 802 address (presumably, a MAC address). This is an important detail from a security point of view. Normally you don't expect a remote node to be able to access machines by MAC address, and many firewall deployments enforce access control solely at the IP level.

KMM: The following was added in 4.1:

        "o  The L-bit is set and the ICMP Extension Structure does not
      identify any local interfaces

  o  The L-bit is clear and the address or addresses found in the
      Interface Identification object appear in neither the IPv4 Address
      Resolution Protocol (ARP) Table nor the IPv6 Neighbor Cache"

And that's an improvement, thank you.

* Similarly, in an IPv4 setting, the proxy can be identified by a routable address, and used to probe a non-routable (RFC 1918) address.

KMM: I don't see added text to point out this as was requested.  Can you point me to the text or add some?

* "The incoming ICMP Extend Echo Request carries a source address that is not explicitly authorized for the incoming ICMP Extended Echo Request L-bit setting" - this implies a per-node whitelist listing all IP addresses that are allowed to probe it. I don't think we mean seriously to list all the addresses that can ping a given node, so this smells like security theater - sorry.

KMM: The last one - I agree with Ron, it is common practice to have explicit allow only lists, at least for any organization I worked. I think this is a good recommendation to keep in the document.

Thank you!

[Ballot comment]
I share Yaron Sheffer's concern about the incoming ACL. Do you really mean to list all the probe-capable nodes?

  or IPv6 Neighbor Cache [RFC4861].  Otherwise, it reports that the
  interface does not exist.
Hmm... So you don't try to ping it yourself? That's interesting.


      the probed node.  The L-bit is clear if the probed interface is
      directly connected to the probed node.
Maybe I'm missing something here, but how does the probing node know?
I.e., can it address by IP address and set L=0?


View Inlinedraft-ietf-intarea-probe.txt:365
      Ethernet is running on the probed interface.  Otherwise, the E-bit
      is clear.
This seems pretty limited. Does "WiFi" count for instance?

[Ballot comment]
This is a fine document.

One small comment about the note in the IANA Considerations section suggesting that the whole section is to be removed before publication. This note is not correct, as IANA needs to be able to point to documents which originated various IANA actions.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Services Operator has completed its review of draft-ietf-intarea-probe-07. If any part of this review is inaccurate, please let us know.

The IANA Services Operator has several questions about the actions requested in the IANA Considerations section of this document. Please see below.

The IANA Services Operator understands that, upon approval of this document, there are five actions which we must complete.

First, in the ICMP Type Numbers registry on the Internet Control Message Protocol (ICMP) Parameters registry page located at:

https://www.iana.org/assignments/icmp-parameters/

two new type numbers are to be registered as follows:

Type: [ TBD-at-Registration ]
Name: Extended Echo Request
Reference: [ RFC-to-be ]

Type: [ TBD-at-Registration ]
Name: Extended Echo Reply
Reference: [ RFC-to-be ]

Second, in the ICMPv6 "type" Numbers registry on the Internet Control Message Protocol version 6 (ICMPv6) Parameters registry page located at:

https://www.iana.org/assignments/icmpv6-parameters/

two new type numbers are to be registered as follows:

Type: [ TBD-at-Registration ]
Name: Extended Echo Request
Reference: [ RFC-to-be ]

Type: [ TBD-at-Registration ]
Name: Extended Echo Reply
Reference: [ RFC-to-be ]

IANA Question --> are these two type numbers to come from the 0-127 range of type numbers or from the 128-255 range?

IANA Question --> The second request in section 7 of the current draft refers to the "Internet Control Message Protocol version 6 (ICMPv6) Parameters" registry, but we believe that the authors intend to make additions to the ICMPv6 "type" Numbers registry instead. Is that correct?

Third, in the Code Fields registry on the Internet Control Message Protocol (ICMP) Parameters registry page located at:

https://www.iana.org/assignments/icmp-parameters/

a new subregistry is to be created for the Extended Echo Reply type created in IANA Action number one above. The new subregistry is managed via IESG Approval or Standards Action. Values in the registry range from 0-15.

There are initial registrations in the new subregistry as follows:

Code Description Reference
-------+---------------------------------+--------------
0 No Error [ RFC-to-be ]
1 Malformed Query [ RFC-to-be ]
2 No Such Interface [ RFC-to-be ]
3 Multiple Interfaces Satisfy Query [ RFC-to-be ]
4-15 Unassigned

IANA Question --> This section of the IANA Considerations also has the following text: "Protocol Flag Bit mappings are as follows: Bit 0 (IPv4), Bit 1 (IPv6), Bit 2 (Ethernet), Bits 3-15 (Reserved)." Is this intended as a separate sub-registry, a note to implementers, or something else?

Fourth, in the ICMPv6 "Code" Fields on the Internet Control Message Protocol version 6 (ICMPv6) Parameters registry page located at:

https://www.iana.org/assignments/icmpv6-parameters/

a new subregistry is to be created for the Extended Echo Reply type created in IANA Action number two above. The new subregistry is managed via IESG Approval or Standards Action. Values in the registry range from 0-15.

There are initial registrations in the new sub-registry as follows:

Code Description Reference
-------+---------------------------------+--------------
0 No Error [ RFC-to-be ]
1 Malformed Query [ RFC-to-be ]
2 No Such Interface [ RFC-to-be ]
3 Multiple Interfaces Satisfy Query [ RFC-to-be ]
4-15 Unassigned

IANA Question --> As was the case with the previous request, this section of the IANA Considerations also has the following text: "Protocol Flag Bit mappings are as follows: Bit 0 (IPv4), Bit 1 (IPv6), Bit 2 (Ethernet), Bits 3-15 (Reserved)." Once again, is this intended as a separate sub-registry, a note to implementers, or something else?

Fifth, in the ICMP Extension Object Classes and Class Sub-types registry on the Internet Control Message Protocol (ICMP) Parameters registry page located at:

https://www.iana.org/assignments/icmp-parameters/

a new sub-registry is to be created for the Interface Identification Object.

The new sub-registry has initial registrations as follows:

C-Type (Value) Description Reference
---------------+-------------------------------+--------------
0 Identifies Interface By Name [ RFC-to-be ]
1 Identifies Interface By Index [ RFC-to-be ]
2 Identifies Interface By Address [ RFC-to-be ]

IANA Question --> what is the maximum value for this new sub-registry?

IANA Question --> what is the registration procedure for this new sub-registry?

The IANA Services Operator understands that these are the only actions required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is only to confirm the list of actions that will be performed.

Thank you,

Amanda Baber
Lead IANA Services Specialist

The following Last Call announcement was sent out (ends 2017-12-13):

From: The IESG
To: IETF-Announce
CC: int-area@ietf.org, Luigi Iannone , draft-ietf-intarea-probe@ietf.org, ggx@gigix.net, suresh@kaloom.com, intarea-chairs@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (PROBE: A Utility For Probing Interfaces) to Proposed Standard


The IESG has received a request from the Internet Area Working Group WG
(intarea) to consider the following document: - 'PROBE: A Utility For Probing
Interfaces'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2017-12-13. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document describes a network diagnostic tool called PROBE.
  PROBE is similar to PING, in that it can be used to test the status
  of a probed interface.  It differs from PING in that it does not
  require bidirectional connectivity between the probing and probed
  interfaces.  Alternatively, PROBE requires bidirectional connectivity
  between the probing interface and a proxy interface.  The proxy
  interface can reside on the same node as the probed interface or it
  can reside on a node to which the probed interface is directly
  connected.  This document updates RFC 4884.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-intarea-probe/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-intarea-probe/ballot/

The following IPR Declarations may be related to this I-D:

  https://datatracker.ietf.org/ipr/2813/

draft-ietf-intarea-probe-06.txt Document Write-up

As required by RFC 4858, this is the current template for the Document Shepherd Write-Up.


(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)? Why is
this the proper type of RFC? Is this type of RFC indicated in the
title page header?

  This document is targeting publication as Proposed Standard.
It is the proper type of RFC since it adds two new types of
  ICMP messages, updating RFC 4884 (which is Proposed standard itself).
The RFC type is clearly marked in the title page header.



(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary:

This document describes PROBE, a new network diagnostic tool.
  PROBE is similar to the PING tool, since it can be used to test the status
  of a probed interface.
  However, differently from PING, it does not require bidirectional connectivity between the probing and probed interfaces.
  Bidirectional connectivity is required only between the probing
  interface and a proxy interface.  The latter can reside on the same node as the probed interface or it can reside on a node to which the probed interface is directly connected. This make PROBE useful in situations where PING would not work, e.g.:
  o  The probed interface is unnumbered
  o  The probing and probed interfaces are not directly connected to
      one another.  The probed interface has an IPv6 link-local address,
      but does not have a more globally scoped address
  o  The probing interface runs IPv4 only while the probed interface
      runs IPv6 only
  o  The probing interface runs IPv6 only while the probed interface
      runs IPv4 only
  o  For lack of a route, the probing node cannot reach the probed
      interface.

Working Group Summary:

The tool proposed in the document document simply overcomes some of the PING shortcomings, and as such has raised interest. During the various presentations in the IntArea meetings no technical objections have ever been raised. Several people have commented on the document and authors addressed these comments.

Document Quality:

Are there existing implementations of the protocol? Have a significant
number of vendors indicated their plan to implement the specification?
Are there any reviewers that merit special mention as having done a
thorough review, e.g., one that resulted in important changes or a
conclusion that the document had no substantive issues? If there was a
MIB Doctor, Media Type or other expert review, what was its course
(briefly)? In the case of a Media Type review, on what date was the
request posted?

There is at least one implementation (by Juniper Networks) of the proposed
mechanism.


Personnel:

Who is the Document Shepherd?

        Luigi Iannone


Who is the Responsible Area Director?

        Suresh Krishnan



(3) Briefly describe the review of this document that was performed by
the Document Shepherd. If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.


  I reviewed carefully the document. The text is clear and understandable.
On the document that past the WG Last Call I had some editorial
changes concerning the IANA considerations section.
  Version -06 of the document addressed the issue.



(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

  As the document shepherd I have no concerns.



(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

  No broader review, going beyond the normal IETF process, is required
  for this document.



(6) Describe any specific concerns or issues that the Document
Shepherd has with this document that the Responsible Area Director
and/or the IESG should be aware of? For example, perhaps he or she is
uncomfortable with certain parts of the document, or has concerns
whether there really is a need for it. In any event, if the WG has
discussed those issues and has indicated that it still wishes to
advance the document, detail those concerns here.

  I have no specific concerns or issues to point out.



(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP
78 and BCP 79 have already been filed. If not, explain why?

    All authors have made conforming IPR disclosure (see next point).



(8) Has an IPR disclosure been filed that references this document? If
so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

  There is an existing IPR disclosure:
    https://datatracker.ietf.org/ipr/search/?submit=draft&id=draft-ietf-intarea-probe
    Authors are unaware of any additional IPR to be disclosed.




(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it?

    Consensus has been reached smoothly for this document.



(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise the areas of conflict in separate
email messages to the Responsible Area Director. (It should be in a
separate email because this questionnaire is publicly available.)

  Nobody did show discontent nor threatened an appeal.



(11) Identify any ID nits the Document Shepherd has found in this
document. (See http://www.ietf.org/tools/idnits/ and the
Internet-Drafts Checklist). Boilerplate checks are not enough; this
check needs to be thorough.

/tmp/draft-ietf-intarea-probe-06.txt:

  Checking boilerplate required by RFC 5378 and the IETF Trust (see
  https://trustee.ietf.org/license-info):
  ----------------------------------------------------------------------------

    No issues found here.

  Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt:
  ----------------------------------------------------------------------------

    No issues found here.

  Checking nits according to https://www.ietf.org/id-info/checklist :
  ----------------------------------------------------------------------------

    No issues found here.

  Miscellaneous warnings:
  ----------------------------------------------------------------------------

    (Using the creation date from RFC4884, updated by this document, for
    RFC5378 checks: 2005-09-19)

  -- The document seems to lack a disclaimer for pre-RFC5378 work, but may
    have content which was first submitted before 10 November 2008.  If you
    have contacted all the original authors and they are all willing to grant
    the BCP78 rights to the IETF Trust, then this is fine, and you can ignore
    this comment.  If not, you may need to add the pre-RFC5378 disclaimer.
    (See the Legal Provisions document at
    https://trustee.ietf.org/license-info for more information.)


  Checking references for intended status: Proposed Standard
  ----------------------------------------------------------------------------

    (See RFCs 3967 and 4897 for information about using normative references
    to lower-maturity documents in RFCs)

    No issues found here.

    Summary: 0 errors (**), 0 flaws (~~), 0 warnings (==), 1 comment (--).

    Run idnits with the --verbose option for more detailed information about
    the items above.
--------------------------------------------------------------------------------



(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

  No formal review is required.



(13) Have all references within this document been identified as
either normative or informative?

    Yes.



(14) Are there normative references to documents that are not ready
for advancement or are otherwise in an unclear state? If such
normative references exist, what is the plan for their completion?

There are no normative references in unclear state.



(15) Are there downward normative references references (see RFC
3967)? If so, list these downward references to support the Area
Director in the Last Call procedure.

  There are no downward normative references.



(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are
not listed in the Abstract and Introduction, explain why, and point to
the part of the document where the relationship of this document to
the other RFCs is discussed. If this information is not in the
document, explain why the WG considers it unnecessary.

No existing RFC's status will change due to the publication
of this document.
  Note, however, that this document UPDATES RFC4884 since it defines two new ICMP message types and an ICMP extension object.
  This is stated in the header, the abstract and the body of the document.




(17) Describe the Document Shepherd's review of the IANA
considerations section, especially with regard to its consistency with
the body of the document. Confirm that all protocol extensions that
the document makes are associated with the appropriate reservations in
IANA registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that newly created IANA registries include
a detailed specification of the initial contents for the registry,
that allocations procedures for future registrations are defined, and
a reasonable name for the new registry has been suggested (see RFC
5226).

I requested some editorial changes from -05 version for the document so to better clarify the IANA section.
  This document instruct IANA to allocate 2 new ICMPv4 type code-points and 2 new ICMPv6 code-points for the two newly defined messages. Additionally a new Class-Num code-point is requested for the newly defined Interface Identification Object.
  The above results as well in the addition of  specific entries to the following existing registries:
  o "ICMP Type Number" registry
  o "Internet Control Message Protocol version 6 (ICMPv6) Parameters" registry
  o "ICMP Extension Object Classes and Class Sub-types" registry
  The content of each requested entry is defined in the IANA Considerations section.
  No creation of new registries is demanded.



(18) List any new IANA registries that require Expert Review for
future allocations. Provide any public guidance that the IESG would
find useful in selecting the IANA Experts for these new registries.

No expert review is required.



(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

  The document does not contain anything written in a formal
  language, hence, no validation and/or check has been
  performed.