On 5/18/2004 3:02 PM, Matthew Elvey wrote:
On 5/18/2004 10:05 AM, Eric A. Hall sent forth electrons to convey:
Take a look at RP which uses TXT RR targets that are sometimes bound
to the associated domain. Every other experimental use is equally
valid.
SPF works just fine with RP. RP is more commonly defined a separate
type: dig elvey.com RP returns ... ;; ANSWER SECTION: elvey.com.
7201 IN RP postmaster.elvey.com. . ... See RFC 1183
<http://www.dns.net/dnsrd/rfc/#rfc1183>. Even if dig elvey.com TXT is
correct for RP, this still isn't a problem. Say matthew.elvey.com were
my MARID-protected domain. Oh, no - I'm using 2 different experimental
TXT RRs. No problem - take a look.
Your example and understanding are both incorrect.
ftp://ftp.rfc-editor.org/in-notes/rfc1183.txt
| 2.2. The Responsible Person RR
| RP has the following format:
|
| <owner> <ttl> <class> RP <mbox-dname> <txt-dname>
|
| Both RDATA fields are required in all RP RRs.
Your example omits the TXT target, which is the point. You asked about
existing RRs that use TXT, and RP is an example of an RR that *requires*
sister TXT RRs, and which are commonly bound to the same name.
Here's a real example from a long-term deployment:
ehsco.com. 28800 IN RP admins.ehsco.com. admins.ehsco.com.
The second reference to admins is a pointer to a TXT RR which happens to
exist at the admins.ehsco.com domain name. Note that I purposefully put it
there because I didn't want it at the top of the zone.
Collision with other TXT RRs isn't a problem.
You are incorrect and your tense is wrong. Not only do other TXT RRs
already exist for other usages, but you need to prevent them from further
colliding in the future as well. You've already failed the first point;
please provide the enforcement text you plan on using to keep this from
ever happening again.
But the fraction of the servers out there that are so modern that they
support new RRs is what? I mentioned the resolvers.
It's 100% of the base that will use them if they want them. They aren't
rare or difficult to deploy.
There is no necessary or even good reason to use TXT RRs.
--
Eric A. Hall http://www.ehsco.com/
Internet Core Protocols http://www.oreilly.com/catalog/coreprot/