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Re: What do people use public suffix for?
From: Jay Ashworth <jra () baylink com>
Date: Mon, 15 Apr 2013 12:00:23 -0400 (EDT)

----- Original Message -----
From: "John Levine" <johnl () iecc com>

The public suffix list contains points in the DNS where (roughly
speaking) names below that point are under different management from
each other and from that name. It's here: http://publicsuffix.org/

The idea is that abc.foo.com and xyz.foo.com have the same management,
but abc.co.uk and xyz.co.uk do not.

You don't have to tell me that it's a gross crock, but it seems to
be a useful one. What do people use it for? Here's what I know of:

* Web browsers use it to manage cookies to keep a site from putting
cookies that will affect other sites, e.g. abc.foo.co.uk can set a
cookie for foo.co.uk but not for co.uk.

* DMARC (www.dmarc.org) uses it to find a policy record in the DNS
that describes a subtree, e.g., if you get mail that purports to be
from eBay () reply1 ebay com it checks the policy at ebay.com.

What other current applications are there?

Seems to me that it's a crock because *it should be in the DNS*.

I should be able to retrieve the AS (administrative split) record 
for .co.uk, and there should be one that says, "yup, there's an
administrative split below me; nothing under there is mine unless 
you also get an exception record for a subdomain".

The people who know authoritatively that their subdomains are within
someone else's administrative span of control *are the people who own
those domains*.


-- jra
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com         2000 Land Rover DII
St Petersburg FL USA               #natog                      +1 727 647 1274

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