> On 21 Jun 2018, at 12:25 am, Petr Špaček <petr.spa...@nic.cz> wrote:
> 
> On 20.6.2018 16:10, Paul Wouters wrote:
>> On Wed, 20 Jun 2018, Petr Špaček wrote:
>> 
>>> it seems that current specification of DNS cookies in RFC 7873 is not
>>> detailed enough to allow deployment of DNS cookies in multi-vendor
>>> anycast setup, i.e. a setup where one IP address is backed by multiple
>>> DNS servers.
>>> 
>>> The problem is lack of standardized algorithm to generate server
>>> cookie from a shared secret. In practice, even if users manually
>>> configure the same shared secret, Knot DNS and BIND will use diffrent
>>> algorithm to generate server cookie and as consequence these two
>>> cannot reliably back the same IP address and have DNS cookies enabled.
>>> 
>>> One of root server operators told me that they are not going to enable
>>> DNS cookies until it can work with multi-vendor anycast, and I think
>>> this is very reasonable position.
>>> 
>>> So, vendors, would you be willing to standardize on small number of
>>> server cookie algorithms to enable multi-vendor deployments?
>> 
>> I think this is a good idea but there are already two examples in RFC
>> 7873 for cookie generation. Is there a problem with those examples, or
>> is there only a lack of options in the implementation to configure
>> these? If the latter, than no new IETF work would be needed.
> 
> These are mere examples and not specifications with all the details
> necessary for reliable interoperability.

The server cookie examples have all the details required to build a 
interoperable
implementation.  i.e. with the same inputs you will get the same outputs.

> E.g. when a cookie is "old" according to B.2.?
> E.g. are there privacy considerations with plain HMAC vs. encryption?


> Besides this, BIND defaults to AES-based algorithm which is not
> specified in the RFC and Knot DNS has its own because developers
> considered the BIND's approch overkill.
> 
> If we decide to standardize we need to find a reasonable algorihm and
> standardize all its variables to make it work without run-time
> synchronization (posssibly except key rotation but it can be done
> avoided as well).
> 
> This message is for other DNS vendors to see if there is an interest in
> standardizing something we can all share and operators use in practice.
> 
> -- 
> Petr Špaček  @  CZ.NIC
> 
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-- 
Mark Andrews, ISC
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PHONE: +61 2 9871 4742              INTERNET: ma...@isc.org

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