Re: DNS Query Format

At 07:02 PM 3/27/2005 -0500, Radu wrote:

> David MacQuigg wrote:
>
> > > One of the 'ground rules' of SPF (current versions) is that is should not
> > > require any change to the existing DNS protocols.
> > Then SPF is already sunk.  It requires a new resource record.
> >
> > > Now there is nowhere within
> > > the current _protocol_ in which you could carry the IP address information
> > > required, so one has to resort to a 'trick'.
> > I would be very surprised if the designers of DNS did not anticipate the 
> > need for new and different information to be added to a query.  Looks to 
> > me like they even have an "additional information" field for that 
> > purpose.  Please tell me where I find any prohibition on adding 
> > additional information to a query.
> Oh, they did think about future record types. section 3.6 in RFC1035 deals 
> with the how and when it should be done.
> It is not a technical reason why SPF should not require new 
> infrastructure, but a business one. Time-to-market would be much slower if 
> it had all types of requirements.
> Also, since the effectiveness of SPF cannot be empirically demonstrated, 
> it would be a hard uphill struggle to get DNS changes standardized, and 
> even a tougher struggle to get them implemented.
> So that's the theory, the new RRs can be added. The reality is that it's 
> so close to impossible, that 'impossible' becomes a good approximation.
> The last revision to DNS was in 1987, 18 years ago. So the fact that the 
> DNS standard has been through the boom and bust of .com, when the millions 
> of dollars were flying everywhere and there was a new .com-related 
> protocol under every pile of horse-poop, is telling that it's not easy.
> I thought this requirement of not messing with the existing infrastructure 
> was one of the best decisions concerning SPF.
What do you mean by new "infrastructure"?  I guess that doesn't include a 
new record type, because draft-schlitt-spf section 3.11 calls for a new SPF 
record type.
Anyway, back to the question of including an IP address as "additional 
information" in the SPF query.  This doesn't require a new record type, and 
certainly no new "infrastructure".  Is anyone aware of any specific 
prohibition on doing this?  Is there a problem with existing DNS servers 
not being able to ignore unexpected "additional informtion"?
-- Dave

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