On Wed, 24 May 2023 at 19:30, Tommy Pauly <tpa...@apple.com> wrote: > > > On May 24, 2023, at 12:00 AM, tirumal reddy <kond...@gmail.com> wrote: > > On Wed, 24 May 2023 at 01:48, Tommy Pauly <tpauly= > 40apple....@dmarc.ietf.org> wrote: > >> Using length=2 and INFO-CODE=0 sounds fine to me. >> >> For the dependency on draft-ietf-add-resolver-info, I don't think we need >> to impose that dependency. I'd much prefer to allow clients to look at that >> optionally, but still be able to include the hint and use the extra text if >> it parses correctly. >> > > Dependency on draft-ietf-add-resolver-info was added to address the threat > where an attacker might inject (or modify) the EDE EXTRA-TEXT field with an > DNS proxy or DNS forwarder that is unaware of EDE.More details are > discussed in Section 10 of the draft. > > > Using encrypted DNS to a known/trusted resolver can achieve this as well, > so I think it is better as a recommendation of one way, but not a required > way. >
Works for me, we will update the draft. -Tiru > > Tommy > > > Cheers, > -Tiru > > >> >> Tommy >> >> On May 23, 2023, at 9:52 AM, Dan Wing <danw...@gmail.com> wrote: >> >> EDE length=2 with INFO-CODE=0 works nicely. >> >> Also because non-EDE-aware DNS responders can be vulnerable to attacks >> described in Security Considerations, the Security Considerations section >> currently suggests clients use draft-ietf-add-resolver-info to check if >> server supports EDE. This needs better clarification in the document that >> client has to check draft-ietf-add-resolver-info before including EDE OPT >> in its DNS query. This check will further help interop by only sending EDE >> in requests to servers that indicated support via >> draft-ietf-add-resolver-info. However, it creates >> draft-ietf-add-resolver-info as another hurdle to deployment of Structured >> DNS error. Thoughts? >> >> (I also put the above text into our github issues; I don't know which >> folks prefer. >> https://github.com/ietf-wg-dnsop/draft-ietf-dnsop-structured-dns-error/issues/26 >> ) >> >> -d >> >> >> On May 22, 2023, at 7:44 PM, Tommy Pauly <tpauly= >> 40apple....@dmarc.ietf.org> wrote: >> >> Thanks, Mark. >> >> For what it's worth, I just ran two other tests, and for both of these >> cases, all of the resolvers I tried did accept the request: >> - Choose a new EDNS option code point (I just tested 50, randomly) >> - Use EDE but set the length to 2 and the error to 0 (other error), >> rather than a length of 0 >> >> Both of these seem viable, and I’ll let the authors and WG decide which >> is the right way forward. >> >> Best, >> Tommy >> >> On May 22, 2023, at 5:00 PM, Mark Andrews <ma...@isc.org> wrote: >> >> >> >> On 23 May 2023, at 02:20, Tommy Pauly <tpauly=40apple....@dmarc.ietf.org> >> wrote: >> >> Hello DNSOP, >> >> In draft-ietf-dnsop-structured-dns-error, there’s a description of how >> clients should indicate that they understand extended DNS errors (EDE) by >> sending an empty EDE option. >> >> >> https://www.ietf.org/archive/id/draft-ietf-dnsop-structured-dns-error-02.html#name-client-generating-request >> >> This is something that makes a lot of sense to me, and provides a great >> way to indicate that a client would prefer to receive proper >> blocked/filtered errors (with possible extra text) as opposed to a forged >> answer. >> >> However, in testing this out, I’m seeing inconsistent compatibility with >> some public resolvers. I was testing enabling this for encrypted resolvers >> only, and I see the following behavior for a sampling of resolvers using >> DoH: >> >> 1.1.1.1 - NOERROR, works fine! >> 9.9.9.9 - NOERROR, works fine! >> 8.8.8.8 - FORMERR on all responses >> dns.adguard-dns.com - SERVFAIL on all responses >> >> Do we think that this should be allowed in queries (and thus this is a >> bug in resolvers like 8.8.8.8 or AdGuard)? Or is there a problem with the >> approach this document is suggesting? >> >> >> RFC 8914 left whether EDE in requests was permitted or not undefined. I >> can see an EDE implementation making the option parser return FORMERR if >> the EDE option length was less than 2 and applying that to both requests >> and responses. RFC 8914 really should have said that EDE in requests >> should be ignored and then there would have been a possibility on extending >> behaviour based on adding EDE to a request. We are already 10 years into >> trying to fix unknown EDNS option behaviour and are still getting FORMERR >> on unknown EDNS options in requests. If the working group want to allow >> extending EDE by adding it to a request is should obsolete RFC 8914 now >> with RFC8914bis that specifies that EDE in requests are to be ignored. >> >> At the moment draft-ietf-dnsop-structured-dns-error-02 really should use >> another EDNS option code point. It really is not backwards compatible with >> EDE the way it is currently specified. >> >> >> Best, >> Tommy >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop >> >> >> -- >> Mark Andrews, ISC >> 1 Seymour St., Dundas Valley, NSW 2117, Australia >> PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org >> >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop >> >> >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop >> >> >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop >> >> >> _______________________________________________ >> DNSOP mailing list >> DNSOP@ietf.org >> https://www.ietf.org/mailman/listinfo/dnsop > > >
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