Since there is no preference factor (such as for MX's), if dns servers are
doing round robin on TXT
records, is that a bug? I was under the impression a query for type TXT should
return ALL TXT
records in scope.
If DNS servers are not explicitly supposed to return all TXT records (1), then
perhaps we should get
2 RR records, SPF1 and SPF2.
Just food for thought, can a DNS spec expert clear up (1)?
Thanks
Terry Fielder
Manager Software Development and Deployment
Great Gulf Homes / Ashton Woods Homes
terry(_at_)greatgulfhomes(_dot_)com
Fax: (416) 441-9085
-----Original Message-----
From: owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
[mailto:owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com]On Behalf Of
william(at)elan.net
Sent: Saturday, September 04, 2004 10:29 AM
To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
Subject: Re: [spf-discuss] spfv1 and spf2/pra
On Sat, 4 Sep 2004, Michael Weiner wrote:
I have noticed an interesting "side-affect" of publishing
both spfv1 and
spf2/pra text records in my dns. When you do a host -t txt
userfriendly.
net you will see the following:
userfriendly.net text "v=spf1 ip4:68.22.33.177/29 ?all"
userfriendly.net text "spf2.0/pra +ip4:68.22.33.177/29 ?all"
however, doing that lookup a few times in a row indicates that the
record i get back first changes, meaning sometimes the spf1
record is
presented first, other times the spf2/pra record is
presented first. My
question about this behavior is fairly straight-forward.
Wont this break
spfv1-only checking domains? Meaning when a domain
receiving email from
userfriendly.net goes to do a lookup, it stands a chance of
NOT getting
back the spfv1 record, and thus might fail the check
thinking there is
no spfv1 record published.
Is there a good method to correct this within bind9 so that
the records
are always presented in the logical order (sfpv1 first then
spf2/pra)
due to current implementation? Otherwise the behavior is
more akin to
round-robin dns implementations.
Its not "akin" to round-robin dns - it is round-robin dns!
Just because these are multiple TXT records, does not make it
any more
different then host with multiple "A" records which is where people
see round-robin comes in most often. DNS works same way for
any record
type, so it will randomly select the order of how these
records are seen
by dns client.
Accidently, randomness of requests to multiple dns root
servers, is based
on the same dns feature; so is randomness of requests to
different nameservers
listed for any given domain (that is why all nameservers need
to be kept
syntronized as far as domain zones they are authoritive for.
--
William Leibzon
Elan Networks
william(_at_)elan(_dot_)net
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