Re: [DNSOP] Erik Kline's Yes on draft-ietf-dnsop-dns-tcp-requirements-13: (with COMMENT)

["Wessels, Duane" <[e-mail]>]

Erik, thanks for the review

> On Oct 26, 2021, at 1:09 PM, Erik Kline via Datatracker <[e-mail]> wrote:
> 
> 
> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> [abstract vs. S1/S3, question]
> 
> * The abstract says:
> 
>   "...strongly
>   encourages the operational practice of permitting DNS messages to be
>   carried over TCP"
> 
>  while section 1 says:
> 
>   "...all DNS resolvers and recursive
>   servers MUST support and service both TCP and UDP queries"
> 
>  and section 3 also some MUST text.
> 
>  Should the abstract be updated to say MUST rather than just
>  "strongly encourages", or is there a subtly in here I'm missing?

Based on the suggestion from Ben, we’ve updated the text:

      <t>This document updates RFC 1123 and RFC 1536.  This
      document requires the operational practice of permitting
      DNS messages to be carried over TCP on the Internet as a Best
      Current Practice.  This operational requirement is aligned with the
      implementation requirements in RFC 7766.  The use of TCP includes



> [S4.1, comment]
> 
> * "Resolvers and other DNS clients should be aware that some servers
>   might not be reachable over TCP.  For this reason, clients MAY want
>   to track and limit the number of TCP connections and connection
>   attempts to a single server."
> 
>  I think the same comment could be made about paths to a server from
>  a given network, e.g., in the case of one network filtering TCP/53 for
>  some reason.
> 
>  I'm not sure how to best reword this to add a per-network notion to
>  TCP connection success tracking, but I did want to note that a mobile
>  client's measure of TCP connection success to a single server might
>  vary from network to network.  (for your consideration)

Is this because mobile devices are more likely to have multiple network choices (say wifi and cellular data) and so the device should include the local network when remembering which works and which doesn’t?

DW