[ietf-dkim] New Issue: ssp-04 DNS operational requirement

[Scott Kitterman]

On Wednesday 02 July 2008 22:40, Douglas Otis wrote:
> 4.3.  ADSP Lookup Procedure
> ,--
>
> |If a query results in a "SERVFAIL" error response, the algorithm
> |terminates without returning a result; possible actions include
> |queuing the message or returning an SMTP error indicating a
> |temporary failure.
>
> '--
> The term "queuing" is rather vague.  In addition SERVFAIL may not be
> visible behind a caching resolver.  In this section it likely to imply
> a message is to be held (as in requeued) pending restoration of DNS
> services, and not that the message is to be queued for delivery to
> individual recipient email-addresses.  This section also imposes a new
> interoperability requirement for SMTP that previously did not exist.
> Prior to the imposition of this requirement, crucial systems with
> addresses assigned within a host address entry could sustain
> communications even in the event of DNS becoming inoperable.
>
> Perhaps the following sentence could be added:
> ---
>
> To ensure message reception remains viable for crucial systems when
> DNS fails, the IP addresses of crucial SMTP clients should be white-
> listed. This will allow ADSP and DKIM to be selectively bypassed
> during such events.
>
Since the cited paragraph doesn't require any particular behavior, I don't see 
the value in this.  

I do wonder if it would be useful to return an error state as a result rather 
than requiring one to infer a protocol related error from no result.

Scott K