Old TLDs never die
When I was at college I briefly used an address of the form lee@cs.mycollege.ac.uk (CS being the subdomain used by the Department of Computer Science). Anyone familiar with the JANET big-endian domain naming convention will have spotted the mistake I made there. And will understand why meddling with top-level DNS can have unexpected effects.
Even though our college had changed over to the little-endian convention,
some mail software, somewhere else in the UK, would assume the my address was written in big-endian notation (since the first part, “cs”, was a valid
TLD) and helpfully translate my address “back” into the little-endian form lee@uk.ac.mycollege.cs before passing it to a server which would attempt a DNS lookup for “mycollege.cs” . An NXDOMAIN would be returned and the mail would bounce. The convention of using the alias lee@dcs.mycollege.ac.uk suddenly started making sense.
.cs was assigned to Czechoslovakia in 1990, but by the time I started
college the country had split into the Czech Republic (.cz) and
Slovakia (.sk) and the TLD was obsolete. By 1995 .cs wasn’t used at all.
And I imagine, beyond references in archives, the last vestiges of the
old JANET naming would have been purged from the Internet by now.
But who knows, maybe there’s a crufty old hack, still running on a server
somewhere that assumes a big-endian format and only converts to little
endian if no match is found. It could have been running unchecked for
a decade, undetectable but for a greater number of failed DNS queries.
Possibly still reliant on the continuing non-existence of domains under .cs.
Well, we’ll find out, ’cause CS is coming back. ISO have redelegated CS to Serbia and Montenegro. It’s very probable that IANA (or rather ICANN) will re-assign the cs TLD.
It’s controversial, but I don’t think it’s a bug in ISO’s practice (there
are only so many alpha-2 representations of a country’s name that fit, and
usually most are already used), and I don’t think it’s a flaw of DNS.
The problem is that DNS domains don’t realistically provide a level of
permanence seemingly required by the URL/URI schemes in use right now.
Nominet introduced the second-level domain .ltd.uk a few years ago, but
received advice that PLCs could not legally refer to themselves as “Ltd”. The solution was to also introduce “.plc.uk“. This means that if a Ltd company becomes a PLC all of its documents named using the DNS derived namespace must also be renamed.
If it’s controversial that a TLD would get recycled after (almost) 10 years of non-use – I’d love to see what happens when they try to pull the plug on SU (the code used by the Soviet Union/CCCP).
After the creation of .ru (Russian Federation) in 1994, the number of domains in actually .su went up and it took on a new status as a sort of autonomous cctld, the identifier of an non-existent state. IANA considers it being phased out
. But according to FID.su there are still over 2000 zones that say otherwise. Perhaps the Russians are just “keeping it warm”?
