Re: consensus call of RR prefix

[Max Kanat-Alexander <mkanat@xxxxxxxxx>]

On Fri, 2004-09-03 at 14:32, Andrew Newton wrote:
>  From the discussion on prefixes for the DNS record, there seems to have 
> been no discernible outcome regarding the use of prefixes for the 
> purposes of avoiding collisions with other DNS records (thus avoiding 
> fallback to DNS over TCP).

	I suspect that I missed some of the comments on this possibly earlier,
as I only recently was able to get to this list. (I thought that perhaps
my developers were on it, but it turns out that they aren't, I think.)
Anyhow, here's my thoughts:

	Any requirement (or even expectation) of DNS over TCP will probably
kill widespread adoption of Sender ID, as DNS over TCP does not work
over a large number of networks. Either it's blocked at a firewall, or
it's disabled on the DNS server.

	If we use a record in domain.tld, we have a higher chance of collision
with some other record than if we use _senders (or some other prefix).
Granted, wildcards are a problem, but they're not really significant,
because obviously the admins who enable wildcards expect spurious DNS
hits and are willing to accept that strange things might happen. Also,
whether I get a collision (or too large of a DNS reply) from querying
*.domain.tld, or domain.tld, it makes no difference to me. The only
thing about using a prefix is that I get to choose to avoid that
collision.

	I don't think it's a huge issue -- what are sysadmins currently using
TXT records in domain.tld for, and how many of them also have wildcards
enabled? I don't know of an extensive number of uses of those things
combined.

	Personally, as a sysadmin, potential implementor, and the fellow who
will have to deal with any angry customers, I'd probably prefer having a
prefix, as I suspect that it will clear up more problems that it will
create.
-- 
Maxwell Kanat-Alexander
2nd Level Tech Support Engineer, USA
Kerio Technologies, Inc.
2041 Mission College Blvd. Suite 100
Santa Clara, CA 95054
Phone: (408) 496-4500
Fax: (408) 496-6902
Web: http://www.kerio.com/support.html