________________________________
From: Linda Dunbar via Datatracker <[email protected]>
Sent: Wednesday, April 9, 2025 3:58 PM
To: [email protected] <[email protected]>
Cc: [email protected] 
<[email protected]>; [email protected] 
<[email protected]>; [email protected] <[email protected]>
Subject: Opsdir ietf last call review of draft-ietf-tls-svcb-ech-07

...

> Mixed SVCB RRSets with and without the “ech” parameter are vulnerable to
> downgrade attacks, yet may occur in multi-provider environments or during
> staged rollouts. Clear operational guidance is needed to mitigate these risks,
> such as prioritizing ECH-capable endpoints using SvcPriority. Deployments
> involving CDNs or multi-CDN setups add complexity around coordination of ECH
> keys and consistent DNS records, and would benefit from best practice
> recommendations.

This situation is addressed in detail already in the Security Considerations: 
https://www.ietf.org/archive/id/draft-ietf-tls-svcb-ech-07.html#section-8-1.  I 
don't believe we have any further recommendations.

> Additionally, diagnosing ECH failures can be difficult due to the lack of
> fallback and visibility. The draft should recommend logging and monitoring
> strategies to help operators detect misconfigurations.

I don't believe we have any relevant recommendations for logging or monitoring. 
 Any such logging would likely not be related to the DNS records, so those 
recommendations would be in draft-ietf-tls-esni or a later draft.

> Key rotation, TTL
> management, and rollback procedures are also important but not addressed.

draft-ietf-tls-esni does already discuss these topics:

Key rotation: 
https://datatracker.ietf.org/doc/html/draft-ietf-tls-esni#name-maintain-forward-secrecy
Rollback: 
https://datatracker.ietf.org/doc/html/draft-ietf-tls-esni#name-misconfiguration-and-deploy
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