> ccTLDs reflect the ISO country codes of each country, and are intended for use by those countries, while gTLDs are arbitrary and reflect the fact that DNS was designed in the US. The ".gov" gTLD, for example, is for use by the US government, while the UK is stuck with ".gov.uk".
Fun fact, the UK's ISO country code is not actually "uk", but "gb". IIRC, ".uk" was grandfathered in (from JANET?) as an exception: ".gb" officially existed for a while in parallel, but no one ever used it and I think it's now defunct.
I love the old interent. I'll confess I have three locality domains and they are wonderful.
I'll confess I have successfully registered a locality domain this year (2025) and it was a little bit fun to go through the weird hoops to get this new domain registered.
I'm also working on/helping out a registrar whose owned died and his widow is resolving what to do with the non-profit.
A related quaint couple of blogs[1][2] if you're feeling nostalgic and motivated to register your own:
Subdivided geographic TLDs are still common in Ontario govts, such as gov.on.ca [1] and tdsb.on.ca for Toronto schools.[2] Both are still in common use.
Australia does the same for organizations regulated at the state level, like schools. However, while all other states/territories do $SCHOOL.$STATE.edu.au:
For Queensland it looks like private schools get a .qld.edu.au domain and state schools get an .eq.edu.au one. For example: https://www.twgs.qld.edu.au/ .
country wide like that must be a bit of a pain for local web admins for those municipalities to make changes through the bureaucracy of government DNS/registrar keyholders. I have a friend who works for a university web services and adding any subdomain takes months to a year+ with committees, boards, meetings and approvals they have to go through first
in what I find to be unfortunate, I have noticed a trend in the reverse direction.
http://shoreviewmn.gov/ should have a dot between the city and the state. they chose some form of human usability over precision. I trust it ever so slightly less, because it is cute before hierarchical.
https://www.mvpschools.org/ formerly https://www.moundsviewschools.org are the domain names for a school district. The fact they chose the P between mv and school (which stands for public) makes it look like phishing or social engineering. It erodes trust in both technical decisions and branding decisions made.
Because domains are hard to read, and people were never taught to read them, we lost out on being able to establish trust because something reads "mv.k12.mn.us" (or preferably us.mn.k12.mv) which is two characters SHORTER than mvpschools.org!
My old school district moved from a localized URL of this kind to a .org a number of years ago (in the early 2010s). It seems to just have become the style, but I never really got it. I'm sure there was a significant cost to migrating what was a perfectly working setup to a whole new domain for website and email!
There are still rules on who gets priority on names: toronto.ca is the government but toronto.com is a news organization; ditto for canada.ca and canada.com; ontario.ca versus ontario.com; etc.
The three/four-level domains are now generally grandfathered.
> Technically speaking, the top of the DNS tree, the DNS root, is a null label referenced by a trailing dot. It's analogous to the '/' at the beginning of POSIX file paths. "gatech.edu" really should be written as "gatech.edu." to make it absolute rather than relative
I have never seen this, but I just tried it and it seems like browsers, even today will happily handle such URLs.
If you work much with DNS, you will know about this. It is known as a FQDN, or a "fully qualified domain name", when the name ends with a .
When you don't use a FQDN, your DNS system is going to try to figure out if you mean a FQDN or actually belong to a subdomain.
On *nix, your /etc/resolv.conf file can have a "search" entries for search domains... that means that a lookup for "foo" will check "foo.bar.com" if "search bar.com" is in your /etc/resolv.conf
This does mean your query could end up making multiple queries to determine if you meant foo. OR foo.bar.com
You can configure how the machine makes the guesses with something called ndots... if you add "ndots 3" to your etc/resolv.conf, then your DNS queries will only try treating the domain as a FQDN if it has at least 3 dots... so for example, it would skip querying for foo as a TLD because it has no dots, and assume you mean "foo.bar.com", saving an unneeded DNS query.
This usually doesn't matter to people, but it can have big performance implications for things like Kubernetes, with lots of .svc.local bits being left off of internal queries and relying on search domains; by increasing the ndots, you avoid a ton of wasted queries.
Some browsers (and web servers, proxies, and other things) treat "example.com" and "example.com." differently for various things, like the default limit of per-domain parallel connections. See for instance https://daniel.haxx.se/blog/2022/05/12/a-tale-of-a-trailing-...
They need to, as when the "." is not present, your search domains are used, but they are not used when the trailing "." is present.
For example, if you enter "ajdfajkhdfkajd.com", and your search domains contain one item called "mycompany.tld", then the browser will first query DNS servers for "ajdfajkhdfkajd.com.", and when an NXDOMAIN is returned, they will try "ajdfajkhdfkajd.com.mycompany.tld." next. If you type "ajdfajkhdfkajd.com." in the browser directly, only the first query is attempted.
Yeah of course adding the extra dot will work. The dot at the end simply means do not try to append the local search domain. Interestingly bad “security” software will often block domains without the trailing dot but permit the one with the trailing dot.
The problem of having two hierarchies in opposite directions means that it is advantageous to store it while reversing one of the hierarchies. I think the earliest Google Search backend used a format like org.myorg.something/something internally. This representation worked great for key-value storage systems where the keys are sorted.
.su is available for registration, I'm not sure what the "in a limited way" is about. In Russia it's used to communicate old-schoolness, approximately.
It definitely is. In Germany, somebody was selling fraudulent public transit e-tickets on an .su domain for a while last year.
Not sure who the “.su” was supposed to appeal to, but they were slightly cheaper than officially licensed ones, which probably helped more than the TLD :)
My community college was occ.cccd.edu when I attended, where cccd.edu was the community college district, and they had registered their domain in 1993, but now the individual colleges have their own domain names, registered in 2002, 2004 and 2007. But there definitely was a time where only 4 year schools and museums were getting new .edus
I didn’t realize how far these had fallen out of fashion. I maintained http://kenn.cr.k12.ia.us for a time, and it was so hard to remember that domain (scarcely easier than an IP address) until I tried to understand it. It’s now kennedy.crschools.us.
My high school is still at www-bths.stjohns.k12.fl.us, and if it wasn’t embedded in my fingertips from working IT there I’d have no idea how anyone is supposed to remember it.
I did sysadmin work for both a .k12.oh.us and a co.countyname.oh.us. Users at both hated the suffix on email addresses. The hierarchy appeals to the nerd in me but I understand the difficulty people had trying to communicate the addresses to others. (Both now use a .com and .gov domain, respectively...)
Cloudflare refuses to accept most locality based domains as delegated because they aren’t listed in the Public Suffix List[1]. So for example you can’t use Cloudflare DNS or get a TLS cert for it from them.
Fortunately they seem to be one of the few (only?) providers who does that. So use another DNS provider and Letsencrypt and you’re good to go.
My school didn't have a domain name or even an email address, or even an internet connection. I think it had 1 or 2 BBC Micros though. I remember playing a game where you had to fire a cannon (choose angle and power) and hit something. Funny how memory works - I assumed I'd remember nothing as so long ago, but remember sitting in the room playing that game now, can't remember why I could though (why I had free access).
Based on the age of the bbc micro, no way it was scorched earth, tanx seems likely (I think it was 3d tanx? I have a vague memory of seeing this in a vintage collection)
> Is it possible to register e.g. X.ca.us domains today? What are the criteria required to do so?
I don't think so. Godaddy won't delegate new third level domains, and I don't think the second level (states) were ever delegated?? But if you can find a city.ca.us that is delegated and that person/organization is willing to register a new name, you could maybe do that.
It did always make me really annoyed they didn’t deprecate .gov, .edu and .mil and transition to moving those under .us (as .gov.us, .edu.us and .mil.us).
Having them as basically US-only just reeks of American exceptionalism which most of the world finds very distasteful.
I'm annoyed that Postel didn't deprecate .com/.net/.org after ccTLDs were introduced. Would have made DNS so much cleaner and at least have a chance of making the hierarchy/tld somewhat meaningful.
I don't think there's any reason to deprecate .edu and move it under the us TLD. Nothing about .edu is US-specific, unlike gov and mil. You could perfectly reasonably have oxford.edu, etc.
> ccTLDs reflect the ISO country codes of each country, and are intended for use by those countries, while gTLDs are arbitrary and reflect the fact that DNS was designed in the US. The ".gov" gTLD, for example, is for use by the US government, while the UK is stuck with ".gov.uk".
Fun fact, the UK's ISO country code is not actually "uk", but "gb". IIRC, ".uk" was grandfathered in (from JANET?) as an exception: ".gb" officially existed for a while in parallel, but no one ever used it and I think it's now defunct.
I love the old interent. I'll confess I have three locality domains and they are wonderful.
I'll confess I have successfully registered a locality domain this year (2025) and it was a little bit fun to go through the weird hoops to get this new domain registered.
I'm also working on/helping out a registrar whose owned died and his widow is resolving what to do with the non-profit.
A related quaint couple of blogs[1][2] if you're feeling nostalgic and motivated to register your own:
[1] https://sleepless.seattle.wa.us/2022-07-01-110449/
[2] http://nguyen.cincinnati.oh.us/locality.html
Subdivided geographic TLDs are still common in Ontario govts, such as gov.on.ca [1] and tdsb.on.ca for Toronto schools.[2] Both are still in common use.
[1] https://kagi.com/search?q=site%3Agov.on.ca&r=ca&sh=lUDz_I8Uq...
[2] https://kagi.com/search?q=site%3ATDSB.on.ca&r=ca&sh=jysEnEgZ...
Australia does the same for organizations regulated at the state level, like schools. However, while all other states/territories do $SCHOOL.$STATE.edu.au:
https://www.abbotsfordps.vic.edu.au/
https://southperthps.wa.edu.au/
https://perthprimary.education.tas.edu.au/
https://nthadelaideps.sa.edu.au/
https://www.nightcliffprimary.nt.edu.au/
https://www.forrestps.act.edu.au/
NSW uses $SCHOOL.schools.nsw.gov.au:
https://innersydneyhighschool.schools.nsw.gov.au/
And Queensland for some bizarre reason uses "eq" ("Education in Queensland", apparently) instead of the standard "qld":
https://townsvillesouthss.eq.edu.au/
For Queensland it looks like private schools get a .qld.edu.au domain and state schools get an .eq.edu.au one. For example: https://www.twgs.qld.edu.au/ .
In Norway we have kommune.no for municipalities.
For example:
- Oslo https://www.oslo.kommune.no/ the largest municipality in terms of population, and home of Oslo the capital of Norway
- Utsira http://www.utsira.kommune.no/ the smallest municipality in terms of population with just 217 people per 2025.
- Nordkapp https://www.nordkapp.kommune.no/ home of the famous Nordkapp (North Cape)
And there is vgs.no for High Schools.
For example:
- Elvebakken videregående skole https://elvebakken.vgs.no/
- Nydalen videregående skole https://nydalen.vgs.no/
- Foss videregående skole https://foss.vgs.no/
These two and some others are called category domains and are managed by Norid, who also run the .no registry as a whole.
https://www.norid.no/en/om-domenenavn/regelverk-for-no/#4.-A...
country wide like that must be a bit of a pain for local web admins for those municipalities to make changes through the bureaucracy of government DNS/registrar keyholders. I have a friend who works for a university web services and adding any subdomain takes months to a year+ with committees, boards, meetings and approvals they have to go through first
Oslo Commune will have control of oslo.kommune.no, i.e. there are DNS records pointing to the commune's DNS server.
It's no different to administer than if they had oslokommune.no.
(Just like dealing with bbc.co.uk is no different to administer than bbc.com.)
in what I find to be unfortunate, I have noticed a trend in the reverse direction.
http://shoreviewmn.gov/ should have a dot between the city and the state. they chose some form of human usability over precision. I trust it ever so slightly less, because it is cute before hierarchical.
https://www.mvpschools.org/ formerly https://www.moundsviewschools.org are the domain names for a school district. The fact they chose the P between mv and school (which stands for public) makes it look like phishing or social engineering. It erodes trust in both technical decisions and branding decisions made.
Because domains are hard to read, and people were never taught to read them, we lost out on being able to establish trust because something reads "mv.k12.mn.us" (or preferably us.mn.k12.mv) which is two characters SHORTER than mvpschools.org!
My old school district moved from a localized URL of this kind to a .org a number of years ago (in the early 2010s). It seems to just have become the style, but I never really got it. I'm sure there was a significant cost to migrating what was a perfectly working setup to a whole new domain for website and email!
For dot-ca, it (used to be) historically mandated that you had to use the 'closest' geographic locale for your domain, which is how we got https://transit.toronto.on.ca (which now goes to https://transittoronto.ca).
At some point CIRA (the non-profit that now runs .ca) stopped making that a requirement.
* https://en.wikipedia.org/wiki/.ca
There are still rules on who gets priority on names: toronto.ca is the government but toronto.com is a news organization; ditto for canada.ca and canada.com; ontario.ca versus ontario.com; etc.
The three/four-level domains are now generally grandfathered.
Freenet.Hamilton.on.ca got me online in the early days!
I recall a rather tech-savvy teacher struggling to write his school-board provided email address for students to submit some assignments to.
Was something reasonable until the @firstclass.schoolname.xyzdsb.city.on.ca or some related silliness
www.gov.mb.ca www.gov.nb.ca www.gov.pe.ca www.gov.ns.ca www.gov.ab.ca www.gov.bc.ca www.gov.on.ca www.gov.nf.ca www.gov.yt.ca www.gov.nt.ca www.gov.nu.ca
Some redirect. Sask. and Que. break the pattern, but both have various government sites under .gov.sk.ca and .gouv.qc.ca (comme de juste).
If you want to create a subdomain, you need DNS delegation (authorization) from the owner/manager of the domain.
So if you want to register xyz.ci.pemberton.nj.us, you need to ask for DNS delegation from the owner/manager of ci.pemberton.nj.us or a higher level.
It's a lot easier to buy the xyz-ci-pemberton-nj.us domain.
Absolutely fascinating history. I thought I knew DNS fairly well and I had no idea that locality-based domains were even a thing.
Ah, what happened to the site design? It used to have a lovely background and monospace text.
> Technically speaking, the top of the DNS tree, the DNS root, is a null label referenced by a trailing dot. It's analogous to the '/' at the beginning of POSIX file paths. "gatech.edu" really should be written as "gatech.edu." to make it absolute rather than relative
I have never seen this, but I just tried it and it seems like browsers, even today will happily handle such URLs.
Neat!
If you work much with DNS, you will know about this. It is known as a FQDN, or a "fully qualified domain name", when the name ends with a .
When you don't use a FQDN, your DNS system is going to try to figure out if you mean a FQDN or actually belong to a subdomain.
On *nix, your /etc/resolv.conf file can have a "search" entries for search domains... that means that a lookup for "foo" will check "foo.bar.com" if "search bar.com" is in your /etc/resolv.conf
This does mean your query could end up making multiple queries to determine if you meant foo. OR foo.bar.com
You can configure how the machine makes the guesses with something called ndots... if you add "ndots 3" to your etc/resolv.conf, then your DNS queries will only try treating the domain as a FQDN if it has at least 3 dots... so for example, it would skip querying for foo as a TLD because it has no dots, and assume you mean "foo.bar.com", saving an unneeded DNS query.
This usually doesn't matter to people, but it can have big performance implications for things like Kubernetes, with lots of .svc.local bits being left off of internal queries and relying on search domains; by increasing the ndots, you avoid a ton of wasted queries.
Some browsers (and web servers, proxies, and other things) treat "example.com" and "example.com." differently for various things, like the default limit of per-domain parallel connections. See for instance https://daniel.haxx.se/blog/2022/05/12/a-tale-of-a-trailing-...
They need to, as when the "." is not present, your search domains are used, but they are not used when the trailing "." is present.
For example, if you enter "ajdfajkhdfkajd.com", and your search domains contain one item called "mycompany.tld", then the browser will first query DNS servers for "ajdfajkhdfkajd.com.", and when an NXDOMAIN is returned, they will try "ajdfajkhdfkajd.com.mycompany.tld." next. If you type "ajdfajkhdfkajd.com." in the browser directly, only the first query is attempted.
what's search domain?
The comment explains it.
> Even today
It's not like it's archaic. You still use the trailing dot when setting up DNS records to ensure they're unambiguous.
Presumably they just split the “domain” part out of the URL on // and the first / and feed that into getaddrinfo, with the OS and DNS doing the rest?
But I agree, it’s definitely neat :)
> "gatech.edu" really should be written as "gatech.edu."
https://www.gatech.edu./ does seem to work for me.
It is interesting that URLs often contain two hierarchies in opposite directions:
https://something.myorg.org/something/more/specific/
Yeah of course adding the extra dot will work. The dot at the end simply means do not try to append the local search domain. Interestingly bad “security” software will often block domains without the trailing dot but permit the one with the trailing dot.
The problem of having two hierarchies in opposite directions means that it is advantageous to store it while reversing one of the hierarchies. I think the earliest Google Search backend used a format like org.myorg.something/something internally. This representation worked great for key-value storage systems where the keys are sorted.
Yes, that's how you're supposed to store URLs as keys in something like Cassandra.
Indeed, back in the 90s I remember trying to decide whether to do foo.bar.com or bar.com/foo for various subsites of my main domain back then.
What is your conclusion?
its not really two hierarchies, its just one written backwards for a while, and then forward.
if you reverse the backwards part you get
https://org.myorg.something./something/more/specific/
the dots separate computers or networks and the slashes separate folders.
well, more pedantically:
https://.org.myorg.something/something/more/specific/
you need the null-label on the left instead of the right.
.su is available for registration, I'm not sure what the "in a limited way" is about. In Russia it's used to communicate old-schoolness, approximately.
It definitely is. In Germany, somebody was selling fraudulent public transit e-tickets on an .su domain for a while last year.
Not sure who the “.su” was supposed to appeal to, but they were slightly cheaper than officially licensed ones, which probably helped more than the TLD :)
The notion that community colleges can't use .edu no longer seems true. When I took community college classes, I got an @my.smccd.edu email address.
The rules changed several times.
My community college was occ.cccd.edu when I attended, where cccd.edu was the community college district, and they had registered their domain in 1993, but now the individual colleges have their own domain names, registered in 2002, 2004 and 2007. But there definitely was a time where only 4 year schools and museums were getting new .edus
I didn’t realize how far these had fallen out of fashion. I maintained http://kenn.cr.k12.ia.us for a time, and it was so hard to remember that domain (scarcely easier than an IP address) until I tried to understand it. It’s now kennedy.crschools.us.
My high school is still at www-bths.stjohns.k12.fl.us, and if it wasn’t embedded in my fingertips from working IT there I’d have no idea how anyone is supposed to remember it.
I did sysadmin work for both a .k12.oh.us and a co.countyname.oh.us. Users at both hated the suffix on email addresses. The hierarchy appeals to the nerd in me but I understand the difficulty people had trying to communicate the addresses to others. (Both now use a .com and .gov domain, respectively...)
The good old Internet was "del.icio.us".
Cloudflare refuses to accept most locality based domains as delegated because they aren’t listed in the Public Suffix List[1]. So for example you can’t use Cloudflare DNS or get a TLS cert for it from them.
Fortunately they seem to be one of the few (only?) providers who does that. So use another DNS provider and Letsencrypt and you’re good to go.
[1] https://en.wikipedia.org/wiki/Public_Suffix_List
My school didn't have a domain name or even an email address, or even an internet connection. I think it had 1 or 2 BBC Micros though. I remember playing a game where you had to fire a cannon (choose angle and power) and hit something. Funny how memory works - I assumed I'd remember nothing as so long ago, but remember sitting in the room playing that game now, can't remember why I could though (why I had free access).
> a game where you had to fire a cannon (choose angle and power) and hit something.
Scortched Earth?
Scorched Earth was such a fun game! Many hours were lost at our small home LAN parties playing SE and Quake/2/3
Or one of its predecessors, Tanx.
Based on the age of the bbc micro, no way it was scorched earth, tanx seems likely (I think it was 3d tanx? I have a vague memory of seeing this in a vintage collection)
Are you talking about Pocket Tanks?
Wow yes, I also remember my high school's k12 domain name! What an interesting trip down memory lane; wonderful, like most of computer.rip!
Is it possible to register e.g. X.ca.us domains today? What are the criteria required to do so?
> Is it possible to register e.g. X.ca.us domains today? What are the criteria required to do so?
I don't think so. Godaddy won't delegate new third level domains, and I don't think the second level (states) were ever delegated?? But if you can find a city.ca.us that is delegated and that person/organization is willing to register a new name, you could maybe do that.
I grew up with *.pinellas.k12.fl.us and that domain remains seared into my memory.
bergen might have dropped the ball but hunterdon’s still works and is in full use: https://www.co.hunterdon.nj.us/
Library ditched it for hclibrary.us though. Used to be able to telnet to the catalog at pac.hunterdon.lib.nj.us
Many US cities use .us for their official web pages
eg: www.ci.east-palo-alto.ca.us
I had a us local domain back in the early 90s, back when uucp still ruled!
It did always make me really annoyed they didn’t deprecate .gov, .edu and .mil and transition to moving those under .us (as .gov.us, .edu.us and .mil.us).
Having them as basically US-only just reeks of American exceptionalism which most of the world finds very distasteful.
I wonder if some anti-“west” military alliances are eligible to get their own .int just like nato.int
There's a list: https://en.wikipedia.org/wiki/List_of_organizations_with_.in...
I don't see why a non-western military alliance wouldn't be eligible, so long as the meet the criteria — treaty registered with the UN etc.
Even if they dejure meet the requirements, I suspect that IANA would be under heavy political pressure to deny the claim.
I'm annoyed that Postel didn't deprecate .com/.net/.org after ccTLDs were introduced. Would have made DNS so much cleaner and at least have a chance of making the hierarchy/tld somewhat meaningful.
Cope with it, America invented the Internet so yes, we are exceptional and have every right to use whatever TLDs we created first.
I don't think there's any reason to deprecate .edu and move it under the us TLD. Nothing about .edu is US-specific, unlike gov and mil. You could perfectly reasonably have oxford.edu, etc.
Some IRC networks still use naming as such like "server.state.country.dal.net."