What do people use public suffix for?

Mon Apr 15 21:34:16 UTC 2013

"John Levine" <johnl at iecc.com> writes:

> 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?
...

CAs use it as part of a procedure to determine whether it's safe to
issue a wildcard domain (as in, if it's on the list, it's not safe).  See
<https://www.cabforum.org/Baseline_Requirements_V1_1_3.pdf>, section 11.1.3.

They'd really like to have a process which is less ad-hoc.  For
example, it'd be great if these points were annotated in the DNS
itself, perhaps with a record which points to the corresponding
whois server.