Re: List of TLDs, CCTLDs and SLDs like co.uk

MS> does anyone know if and where there is a complete list of TLDs,
MS> country code TLDs and second level domains for those CCTLDs that
MS> always have a 2nd level, like co.uk, edu.au etc. available?

<URL:http://perl.plover.com./Questions3.html>

The answer, given that, is "Yes.".

MS> I need it to strip all levels from an FQDN up to the highest
MS> level that is not an official domain name.

The identity function does that. _All_ domain names in the public DNS
database are official, inasmuch as any of them can be said to be so.

MS> [...] the implementation first tries to lookup [...]

Stop when you reach a domain name suffix that has a non-empty "SOA" resource
record set. A comprehensive list of delegation points is not what you need at
all.

In article <3F0A2B26.B3F07888@tesco.net>,
Jonathan de Boyne Pollard <J.deBoynePollard@tesco.net> wrote:[color=blue]
>Stop when you reach a domain name suffix that has a non-empty "SOA" resource
>record set. A comprehensive list of delegation points is not what you need at
>all.[/color]

Lots of corporate subdomains have SOA records, but I don't think he wants
to stop at things like engineering.company.com -- he wants to keep going to
company.com.

--
Barry Margolin, [email]barry.margolin@level3.com[/email]
Level(3), Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

BM> Lots of corporate subdomains have SOA records, but I don't think
BM> he wants to stop at things like engineering.company.com -- he
BM> wants to keep going to company.com.

He didn't say one way or the other. However, it's not unreasonable to
suppose, given his description of what he is doing, that he might indeed want
exactly that. He might well want the administrative boundaries for his
"automatic proxy config script" to align with the administrative boundaries of
the DNS, and may well indeed want a search to stop at
"engineering.company.com." if that happens to be a "zone" apex. As Peter Koch
pointed out, there's precedent for that sort of thing being a good idea. (-:
There's also evidence, from the world of Active Directory, for the belief that
when large organizations have subdomains that are independent enough to manage
their own namespace, they generally try to avoid mechanisms that are capable
of accidentally being used to apply default settings globally across all
subdomains.

And, as Peter also pointed out, if one chooses not to use the information that
is readily available in the DNS database for this, the other reasonable
solution is to simply require an administrator to explicitly supply the list
of domain names whose subdomains will be searched in the manner described.