Re: draft-ietf-ospf-ospfv3-auth-04.txt

Erblichs <erblichs@EARTHLINK.NET> Wed, 07 July 2004 00:10 UTC

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From: Erblichs <erblichs@EARTHLINK.NET>
Subject: Re: draft-ietf-ospf-ospfv3-auth-04.txt
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Ace, et al,

        I realize that this is a late comment..

        Section 3. Authentication

                But this really applies throughout
                this doc.

      "OSPF packets recieved ... MUST be dropped ..."

        Their is no mention that I have seen that identifies
        an appropriate MISMATCH message that allows the
        recv'r administrator to correct this or other bad
        configurations. Also, can a OSPF router sychronize
        or update its database with another router if a
        percentage of its packets are dropped?

        I keep on thinking that dropped msgs of this type
        need to be tracked and as much information should
        be logged about the xmit'er of the MISMATCHED pkt.

        What happens if some OSPF packets are dropped from
        a router and others are accepted?

        Thus, I would think and this is a bit extreme, if
        a OSPF packet is recieved that has a mismatch in
        any encryption or authentication field(s) from the
        xmit router, the adjacency or its 2-way link status
        should be dropped. The router can not be a trusted
        router if some of its packets are untrusted and/or
        its contents are unknown. Can it?
        Yes, this is assuming that the router-id is known.

        Mitchell Erblich

Acee Lindem wrote:
> Even though this has gone through WG last call it may
> be a good to schedule some time at the San Deigo IETF
> to discuss recent issues and how they are addressed
> in the new draft. Comments?
> ----- Original Message -----
> From: <Mukesh.Gupta@NOKIA.COM>;
> Sent: Monday, July 05, 2004 3:19 PM
> Subject: Re: draft-ietf-ospf-ospfv3-auth-04.txt
> Hi Vishwas,
> Thanks for the comments.  Please see my comments inline..
> > 1. I am not sure we should have a statement which says OSPFv3
> > is only for IPv6.
> > "As OSPFv2 is only for IPv4 and OSPFv3 is only for IPv6,
> > the distinction between the packets can be easily made by
> > IP version. "
> Do you have a replacement statement that you would prefer ?
> As the IP protocol type value for OSPF and OSPFv3 is same,
> we have to depend upon the IP version to separate OSPF and
> OSPFv3 packets.
> > 2. I think the value of next header field in the ESP header
> > to indicate OSPFv3 should be specified, though it may seem
> > a trivial question.
> Why do you think it should be specified?  Whenever ESP is
> applied to any IP packet, the IP Protocol Type field value
> from the IP header is copied to the next header field of
> ESP/AH.  There are no exceptions here.
> > 3. ESP already states that "integrity-only (MUST be supported)"
> > do we really need to put down "ESP with NULL encryption MUST be
> > supported in transport mode".
> An implementation may support ESP/AH that conform to ESP/AH RFCs,
> but the idea of putting this in this draft was to ensure that the
> user is allowed to use the specified combinations for securing
> the OSPF traffic.  So that 2 independent secured OSPF
> implementations have at least one common combination to configure.
> Do you see any harm in putting this text in the draft ?
> > 4. I think we may want to state that Authentication service must
> > always be supported whenever we do encryption. Our primary aim is
> > to have data integrity right(anyway encryption only service is a
> > MAY for ESP)?
> Doesn't the sentence "Providing confidentiality to OSPFv3 in addition
> to authentication is optional." imply that ?  Or would it better to
> replace
> "ESP with non-null encryption in transport mode MUST be used
> for providing the confidentiality to OSPFv3."
> with
> "ESP with non-null encryption and non-null authentication in transport
> mode MUST be used for providing the confidentiality to OSPFv3."
> > 5. OSPF packets received in clear text or with incorrect AH
> > Integrity Check Value (ICV) MUST be dropped when authentication is
> > enabled.
> > Do we mean only AH/ICV or do we need ESP ICV too? Besides do we
> > need to state about combined mode algorithms like AES-CCM where
> > ICV may not checked even when authentication is done.
> It should be AH/ESP ICV.  I will replace "AH" with "AH/ESP" in the
> next version.
> The draft for AES-CCM says "it is inappropriate to use this CCM
> with statically configured keys".  We are using staticaly configured
> keys here.  So should we just NOT use AES-CCM ?
> > 6. SA Granularity and Selectors section - I think you are referring
> > to parallel links we may want to state that too.
> No I am not referring to parallel links (if you mean 2 links connecting
> the same routers).  It should be possible to use the same SA for multiple
> interfaces belonging to even different areas.
> > 7. Changing Keys may also be required in case of sequence number rollover.
> How is the user going to know about the sequence number rollover ?
> so that he/she can initiate the key change.  That brings an interesting
> question.  If the user never changes the keys, what happens when the
> sequence number rollovers ?
> > 8. Would we want to refer to the newer drafts for ESP/AH drafts rather
> > then the old RFC's itself?
> That's a good idea but the problem is that if we put the new drafts
> as normative references, this draft will not be published before those
> drafts.  Do we want to block the draft waiting for those drafts ?
> The draft was reviewed by the IESG on June 26th and the comments can
> be seen at
> We will be working on addressing all the comments now and will publish
> an updated version of the draft probably after the IETF 60th.
> regards
> Mukesh