Hi Keith.

Thanks for the comments. My responses inline.

On Jan 19, 2011, at 2:36 AM, Keith Welter wrote:


1. The last paragraph of section 2 seems to be making an argument against 
supporting QCD.  Would it be possible to add a counterpoint or to reword the 
paragraph?  When I got to the end of the document, I found that section A.4 had 
the counterpoint I was looking for.  Perhaps add a reference to section A.4 
from the last paragraph of section 2.

OK. How about:

   Some existing IKEv2 implementations already do that (i.e., both
   shorten timeouts or limit number of retries) based on these kind of
   hints and also start liveness checks quickly after the other end goes
   silent.  However, see Appendix A.4 for a discussion of why this may
   not be enough.

2. In section 4.1 (Notification Format) the TOKEN_SECRET_KEY fields size is 
given as "(16-128 octets)".  I suggest replacing this with "(variable)" so that 
the specific size requirement only appears in one place (section 5): "Tokens 
MUST be at least 16 octets long, and no more than 128 octets long, to 
facilitate storage and transmission."

OK.

3. In section 4.3, the text "SHOULD soon initiate an INFORMATIONAL exchange as 
follows" is vague.  How soon is soon?  How about: "SHOULD initiate an 
INFORMATIONAL exchange immediately after the CREATE_CHILD_SA exchange as 
follows".  Or, omit "immediately" if that is not strictly necessary.

OK, and I went with "immediately". If the initiator doesn't do it, QCD does not 
work.

4. The final paragraph in section 4.3 mentions "key rollover" and "secret QCD 
keys" but these concepts have not been defined.  It seems like this material 
would fit better in section 5 (Token Generation and Verification) where the 
cryptographic mechanism for QCD token generation is recommended.

I disagree with this. Section 4 has all the information about using the 
notification payload. How about if I add a pointer like this:

   The INFORMATIONAL exchange described in this section can also be used
   if QCD tokens need to be replaced due to a key rollover.  However,
   since token takers are required to verify at least 4 QCD tokens, this
   is only necessary if secret QCD keys are rolled over more than four
   times as often as IKE SAs are rekeyed.  See Section 5.1 for an
   example method that uses secret keys which may require rollover.


5. Similarly, section 4.5 mentions "periodic rollover of the secret used for 
token generation" but token generation has not yet been covered.  Perhaps a 
better solution than what I recommended in the prior comment would be to move 
all of  section 5 (i.e. 5 through 5.3) before section 4.  That way, token 
generation would be discussed before any mention of token secrets, keys or 
rollover in sections 4.1 through 4.5.

See last remark.

6. The first sentence on page 18 is an orphan.

That's just how the xml2rfc utility formats it. When (and if) it gets 
published, the RFC editor takes care of these stylistic issues.

7. In section 11, "contrinuted" should be "contributed".

Will be fixed in -04.

8. Section A.1 says, "The disadvantage here, is that in IKEv2 an authentication 
exchange MUST have a piggy-backed Child SA set up."  RFC 6023 specifies a 
childless IKE SA initiation so that sentence is not true for implementations 
that support RFC 6023.

True, but since RFC 6023 is experimental, I would like to leave this sentence. 
Also, the important part is the next paragraph, which says that sometimes 
setting up a new IKE SA is not possible for the former responder.


Thanks,

Keith Welter
IBM z/OS Communications Server Developer
1-415-545-2694 (T/L: 473-2694)


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