[Gen-art] Re: Gen-ART review of draft-ietf-v6ops-ipsec-tunnels-04.txt
Pekka Savola <psavola@funet.fi> Thu, 18 January 2007 12:18 UTC
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From: Pekka Savola <psavola@funet.fi>
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Cc: david.kessens@nokia.com, fred.baker@cisco.com, Hannes.Tschofenig@siemens.com, gen-art@ietf.org, kurtis@kurtis.pp.se, mohanp@sbcglobal.net, rfg@acm.org
Subject: [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-ipsec-tunnels-04.txt
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Hello David (B.), Brian, A new version of the draft has been submitted. We believe it addresses your comments. Please check it out. This was the only DISCUSS. http://tools.ietf.org/wg/v6ops/draft-ietf-v6ops-ipsec-tunnels/ Below are a few notes where it isn't 100% clear whether the desired impact was achieved. - section 5.0 almost in its entirety (most text moved from deleted section 5.2). NOTE: I think section 5 is still a bit unclear of when "interface" refers to "IP interface" and when "tunnel interface". NOTE: we also now explicitly state that ingress filtering configuration must be applied manually [it cannot be negotiated as part of IKE or IPsec configuration, for example]. This is likely good enough, but I think David Black was looking for a bit more than that -- unfortunately, I don't think any IPsec-side automation can be provided.. On Sat, 9 Dec 2006 Black_David@emc.com wrote: > I have been selected as the General Area Review Team (Gen-ART) > reviewer for this draft (for background on Gen-ART, please see > http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html). > > Please wait for direction from your document shepherd > or AD before posting a new version of the draft. > > Document: draft-ietf-v6ops-ipsec-tunnels-04.txt > Reviewer: David L. Black > Review Date: 9 December 2006 > IESG Telechat date: 14 December 2006 > > Summary: > > This draft is on the right track, but has open issues, described > in the review. > > Comments: > > As an informational document whose primary purpose is to explain how > to use protocols specified elsewhere, clarity is of primary importance. > While I was able to figure out what the draft is trying to say, it > needs attention. > > The open issues include the clarity problems in Section 4 that rise to > the level of possible or actual technical misstatements, the lack of > explanation of requirements in Section 5.2, and the missing IPsec > details. > > My detailed comments are as follows: > > The recommendation against tunnel mode should be included in the > abstract. > > Section 4 has some wording problems: > > 1. [RFC2401] does not allow IP as the next layer protocol in traffic > selectors when an IPsec SA is negotiated. [RFC4301] also allows > IP as the next layer protocol (like TCP or UDP) in traffic > selectors. > > The "also" is susceptible to misreading. The second sentence should > be rephrased to: "In contrast, [RFC4301] does allow ..." > > 2. [RFC4301] assumes IKEv2, as some of the new features cannot be > negotiated using IKEv1. It is valid to negotiate multiple > traffic selectors for a given IPsec SA in [RFC4301]. This is > possible only with [RFC4306]. If [RFC2409] is used, then > multiple SAs need to be set up for each traffic selector. > > The last sentence is incorrect as written ("set up" needs to be > replaces by "set up, one for each" to correct it) and the use of > RFC numbers for protocol names is semi-opaque. The following would > be much clearer: > > 2. [RFC4301] assumes IKEv2, as some of the new features cannot be > negotiated using IKEv1. It is valid to negotiate multiple > traffic selectors for a given IPsec SA in [RFC4301]. This is > possible only with IKEv2. If IKEv1 is used as specified in > [RFC2409], then each traffic selector requires a separate SA. > > I strongly recommend use of the protocol names instead of just RFC > numbers for clarity throughout the draft, and using both (e.g., > "IKEv1 [RFC2409]") is an acceptable alternative. > > Table 1 in Section 5 uses acronyms for addresses in the "Contains" > column that need to be defined before they are used. > > Section 5.2 discusses the consequences of whether the endpoint > of an IPsec tunnel-mode SA is modeled as an IPv6 interface or > not. It should say that there is always an IPv6 interface at > the endpoint of a IPv6-in-IPv4 tunnel, and the discussion of > whether to model the SA as an interface is concerned with > whether the functionality of an IPv6 interface is realized by > the IPsec SA or outside of it. > > It should also be stated that all uses of the word "interface" > refer to an IPv6 interface, and that the phrase "tunnel interface" > refers to an IPv6 interface at the endpoint of an IPv6-in-IPv4 > tunnel, independent of whether the tunnel is realized by IPsec > tunnel mode. The end of Section 1 would be a good place to > do this. The use of the phrase "IP interface" in Section A.1 > is considerably clearer than the use of "interface" without "IP" > in Section 5.2 - using "IP interface" throughout Section 5.2 > (and for that matter the entire draft) would improve readability. > > The three requirements in Section 5.2 are generally applicable, > and should not be buried in Section 5.2's discussion of IPsec > tunnel mode. The requirements also lack explanations of why > they are requirements. At a minimum, the statement of the > requirements should be moved into Section 5 (before 5.1), but > I would suggest moving them to the end of Section 3 and adding > a discussion of why these requirements are important (e.g., what > goes wrong if they're not met) with reference to the scenarios > described in Section 3. > > Cross-checking this draft against the elements in Section 8 > of draft-bellovin-useipsec-05.txt, I find some things that need > attention: > a) Selectors - Yes, specified in Section 5.1 > b) IPsec protocol and mode - Yes, ESP vs. AH is at the > end of section 4 and tunnel-vs-transport is a > major portion of this draft. > c) Key management - Almost. The numerous mentions of > IKE indicate a preference for automatic keying, but > there should also be a strong recommendation against > manual keying, due to the amount of IPv6 traffic that > may use an IPv6-in-IPv4 tunnel. Manual keying of > IKE needs to be clearly distinguished from manual > configuration of the IPv6-in-IPv4 tunnel. The end > of Section 2 would be a good location for these topics. > d) SPD entries - Yes, specified in Section 5.1 > e) Identification forms - Yes, but. The first bullet in > Section 5.3 has a weak recommendation for IPv4 > addresses as identities. The "but" is that ingress > filtering is discussed entirely in the abstract, and > additional discussion is needed about how to determine > what IPv6 ingress filter to use with which IPv4 address > (this may be part of tunnel configuration). > f) Authentication form - Yes, second bullet in section 5.3 > g) IKE versions and modes - No. Section 4 implies that > both IKEv1 and IKEv2 can be used, although IKEv2 is > somewhat preferred - this should probably be stated > explicitly. There is no discussion of IKEv1 Main vs. > Aggressive mode - it would suffice to say that if > IPv4 addresses are used as identities, identity > protection is not required (it's obvious where the > traffic is coming from), making Aggressive mode an > acceptable alternative to Main mode. > h) IPsec support availability - No. This can be side- > stepped to some extent by noting that the IPv6 RFCs > require IPsec support. > > Note that I am not asking that this draft meet all the requirements > in Section 8 of the bellovin-useipsec draft, and in particular, I'm > giving this draft significant slack against the usual IETF > requirement that sufficient mandatory-to-implement elements be > specified for interoperability. With the possible exception of > IKEv1 vs. IKEv2, interoperability requirements belong in the RFCs > that specify the protocols involved. > > Thanks, > --David > ---------------------------------------------------- > David L. Black, Senior Technologist > EMC Corporation, 176 South St., Hopkinton, MA 01748 > +1 (508) 293-7953 FAX: +1 (508) 293-7786 > black_david@emc.com Mobile: +1 (978) 394-7754 > ---------------------------------------------------- > _______________________________________________ Gen-art mailing list Gen-art@ietf.org https://www1.ietf.org/mailman/listinfo/gen-art
- [Gen-art] Gen-ART review of draft-ietf-v6ops-ipse… Black_David
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Fred Baker
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Pekka Savola
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Mohan Parthasarathy
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Mohan Parthasarathy
- [Gen-art] RE: Gen-ART review of draft-ietf-v6ops-… Black_David
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Fred Baker
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Mohan Parthasarathy
- [Gen-art] RE: Gen-ART review of draft-ietf-v6ops-… Black_David
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Pekka Savola
- [Gen-art] Re: Gen-ART review of draft-ietf-v6ops-… Mohan Parthasarathy
- RE: [Gen-art] Re: Gen-ART review ofdraft-ietf-v6o… Black_David