On 3 Jun 2015, at 17:17, Shane Kerr wrote:
On Wed, 03 Jun 2015 13:57:39 +0100
Ray Bellis <r...@bellis.me.uk> wrote:
Whilst discussing 5966-bis with my co-authors connection-close with
the
co-authors, we were reminded of this point I made in
draft-bellis-dnsop-connection-close in relation to ยง7 of RFC 6891:
" TODO: note - the constraint in RFC 6891 appears unnecessarily
strict
- it appears to mandate that the EDNS(0) support indication is on a
per-request basis, but it would be reasonable on a connection-
orientated transport to assume that ANY preceding request on that
connection with an OPT RR is sufficient to indicate that the client
supports EDNS(0)."
Is this something that the WG believes needs to be fixed?
The potential benefit is that a client could omit the OPT RR on
subsequent messages? Seems a relatively small benefit, and there are
costs. (Are there other benefits?)
I agree.
I think there's a baked-in expectation that OPT pseudo-RR is included in
every DNS message, not on every connection (where the transport is
connection-oriented).
While the conventional case of resolver-talks-to-authority makes this
seem like a highly pedantic observation, we can never be sure of what is
happening behind the curtain; ALGs that bridge between transports
(providing a UDP interface on one side but managing a TCP connection
pool on the other, for example) exist, for example.
I think there would need to be a clear benefit before we imagined
changing EDNS signalling semantics to be anything other than
per-message.
Joe
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