At 11:51 PM +0300 5/13/09, Yoav Nir wrote:
>Scott C Moonen wrote:
>>
>> I'm reviewing RFC 4869 and it seems to under-specify the attributes that
>> are needed to achieve real interoperability: it doesn't specify whether to
>> do a phase 2 Diffie-Hellman exchange for perfect forward secrecy, nor
>> does it specify IKEv1 lifetime and lifesize values.  So I am left having to
>> guess at what are appropriate values to use for these attributes.  And
>> once I do choose particular values for PFS and lifesize, is it still correct
>> for me to use the RFC's suite names in reference to them?
>
>Interesting. I hadn't noticed that.
>
>I guess the best thing is to do as in RFC 4308:
>"                                                                          
>...The initiator of this
>   exchange MAY include a new Diffie-Hellman key; if it is included, it
>   MUST be of type..."
>
>IOW it's up to the initiator whether or not to do PFS, and both configurations
>are OK to use the suite name.

That was my intention in RFC 4308; I cannot speak for the authors of RFC 4869.

>As for lifetimes, at least our implementation has a separate configuration for 
>it.
>Lifetimes in IKEv1 are negotiated, so I don't believe it's necessary to 
>actually
>specify it in the RFC.

Fully disagree. "Negotiated" in IKEv1 is the wrong word: the responder either 
accepts what the initiator says, or stops. Most IKEv1 systems require that 
lifetimes match exactly; that's why I had to include section 2.3 in RFC 4308. 
Having said that, it is fine for a profile not to list lifetimes explicitly; it 
just means that the two sides still have to agree to lifefimes out-of-band.

--Paul Hoffman, Director
--VPN Consortium
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