6 ms·

Technically, the shortest domain name is 2 letters: http://dk http://dk

by jpxw 6y ago

deleted 6y ago
[deleted]
RyJones 6y ago
.va used to have an SMTP server.
wincent 6y ago
Chrome won't load that without the trailing dot: http://dk http://dk.
- AnssiH 6y ago
  Loads fine for me without dot in Chrome (tested on Linux and Android).
edent 6y ago
Oh! Now that's nifty. How long have they had that?
keb_ 6y ago
DONKEY KONG
aapeli 6y ago
Also http://ai./ http://ai./ which doesn't redirect you anywhere.
snthd 6y ago
Is http:// http://. possible?
- unicodepepper 6y ago
  Apparently it is possible to do it with local DNS resolution, using your hosts file Not sure how possible it would be on a remote DNS server, or whose authority you'd need to actually do it. [root@host ~]$ curl -v http:// http://. * About to connect() to . port 80 (#0) * Trying 127.0.0.1... * Connected to . (127.0.0.1) port 80 (#0) > GET / HTTP/1.1 > User-Agent: curl/7.29.0 > Host: . > Accept: / > < HTTP/1.1 400 Bad Request < Date: Sat, 15 Aug 2020 15:38:54 GMT < Server: Apache < Content-Length: 347 < Connection: close < Content-Type: text/html; charset=iso-8859-1 < <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>400 Bad Request</title> </head><body> <h1>Bad Request</h1> <p>Your browser sent a request that this server could not understand.<br /> </p> <p>Additionally, a 400 Bad Request error was encountered while trying to use an ErrorDocument to handle the request.</p> </body></html> * Closing connection 0
- ricardo81 6y ago
  Was my thoughts also. Doing a dig, there are no A records for . but they do provide NS records obviously, for all the other TLDs to resolve. Devilish detail is probably in the RFC and likely implementation specific also, as to whether they accept it is a valid request or fail before trying. dig A . ; <<>> DiG 9.11.5-P4-5.1-Debian <<>> A . ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26280 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;. IN A ;; Query time: 3 msec ;; SERVER: 192.168.1.254#53(192.168.1.254) ;; WHEN: Sat Aug 15 18:19:41 BST 2020 ;; MSG SIZE rcvd: 17
- parliament32 6y ago
  Yes, if the root zone (".") published a CNAME or A record. You can simulate this yourself by setting your resolver as the master for "." and giving it an A record. Note that most webservers will barf if you try to send "." in the Host header unless you explicitly configured it. # cat named.conf.local zone "." { type master; file "/etc/bind/db.root"; }; # cat db.root $TTL 60 @ IN SOA localhost. root.localhost. ( 1 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; @ IN NS . @ IN A 209.216.230.240 # dig a . ... ;; QUESTION SECTION: ;. IN A ;; ANSWER SECTION: . 60 IN A 209.216.230.240 # wget http://./ --2020-08-17 09:38:26-- http://./ Resolving . (.)... 209.216.230.240 Connecting to . (.)|209.216.230.240|:80... connected. HTTP request sent, awaiting response... 400 Bad Request 2020-08-17 09:38:26 ERROR 400: Bad Request.
1f60c 6y ago
Does this mean you (theoretically) can’t name a host "dk" on your local network? That seems bad, (even if naming hosts after TLDs is a bad idea).
- MayeulC 6y ago
  Technically, you should be able to have your local host resolve first. To avoid it being resolved and use the TLD instead, use the trailing dot: http://dk./ http://dk./ https://news.ycombinator.com./ https://news.ycombinator.com./ This makes it a FQDN, just like you enter it in your DNS records. Practically, people tend to forget about it, and accessing websites this way sometimes break in unexpected ways when the server doesn't expect the trailing dot in the "host" header. http://www.dns-sd.org./TrailingDotsInDomainNames.html http://www.dns-sd.org./TrailingDotsInDomainNames.html
- kevincox 6y ago
  You shouldn't be doing this anyways. There are reserved TLDs for this like .corp https://tools.ietf.org/id/draft-chapin-rfc2606bis-00.html#new https://tools.ietf.org/id/draft-chapin-rfc2606bis-00.html#ne...
SuperCuber 6y ago
How does this work? Also, why can't nslookup resolve it?
- zuppy 6y ago
  domains are split by the dot, from right to left. what is not visible is that the top level domain is not really the first one. the first one is the root domain (or root zone), which is represented by an empty string. you can try it on any domain, add a dot at the end. it will resolve, but the web server may not be configured to respond to it with the right website. if you want to query a dns server for a top level domain, you have to query the dns that handles it, which in our case is one of the 13 root dns servers. read more here: https://en.m.wikipedia.org/wiki/DNS_root_zone https://en.m.wikipedia.org/wiki/DNS_root_zone https://en.m.wikipedia.org/wiki/Root_name_server https://en.m.wikipedia.org/wiki/Root_name_server
cryptonector 6y ago
Technically it could be shorter still, if only either . had an A RRset, or if there were 1-character TLDs. Just cause those aren't true today, doesn't mean they can't ever be true.

Technically, the shortest domain name is 2 letters: http://dk http://dk

by jpxw 6y ago

Technically, the shortest domain name is 2 letters: http://dk http://dk

deleted 6y ago

[deleted]

RyJones 6y ago

.va used to have an SMTP server.

wincent 6y ago

Chrome won't load that without the trailing dot: http://dk http://dk.

AnssiH 6y ago
Loads fine for me without dot in Chrome (tested on Linux and Android).

edent 6y ago

Oh! Now that's nifty. How long have they had that?

keb_ 6y ago

DONKEY KONG

aapeli 6y ago

Also http://ai./ http://ai./ which doesn't redirect you anywhere.

snthd 6y ago

Is http:// http://. possible?

unicodepepper 6y ago
Apparently it is possible to do it with local DNS resolution, using your hosts file Not sure how possible it would be on a remote DNS server, or whose authority you'd need to actually do it. [root@host ~]$ curl -v http:// http://. * About to connect() to . port 80 (#0) * Trying 127.0.0.1... * Connected to . (127.0.0.1) port 80 (#0) > GET / HTTP/1.1 > User-Agent: curl/7.29.0 > Host: . > Accept: / > < HTTP/1.1 400 Bad Request < Date: Sat, 15 Aug 2020 15:38:54 GMT < Server: Apache < Content-Length: 347 < Connection: close < Content-Type: text/html; charset=iso-8859-1 < <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>400 Bad Request</title> </head><body> <h1>Bad Request</h1> <p>Your browser sent a request that this server could not understand.<br /> </p> <p>Additionally, a 400 Bad Request error was encountered while trying to use an ErrorDocument to handle the request.</p> </body></html> * Closing connection 0
ricardo81 6y ago
Was my thoughts also. Doing a dig, there are no A records for . but they do provide NS records obviously, for all the other TLDs to resolve. Devilish detail is probably in the RFC and likely implementation specific also, as to whether they accept it is a valid request or fail before trying. dig A . ; <<>> DiG 9.11.5-P4-5.1-Debian <<>> A . ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26280 ;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;. IN A ;; Query time: 3 msec ;; SERVER: 192.168.1.254#53(192.168.1.254) ;; WHEN: Sat Aug 15 18:19:41 BST 2020 ;; MSG SIZE rcvd: 17
parliament32 6y ago
Yes, if the root zone (".") published a CNAME or A record. You can simulate this yourself by setting your resolver as the master for "." and giving it an A record. Note that most webservers will barf if you try to send "." in the Host header unless you explicitly configured it. # cat named.conf.local zone "." { type master; file "/etc/bind/db.root"; }; # cat db.root $TTL 60 @ IN SOA localhost. root.localhost. ( 1 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; @ IN NS . @ IN A 209.216.230.240 # dig a . ... ;; QUESTION SECTION: ;. IN A ;; ANSWER SECTION: . 60 IN A 209.216.230.240 # wget http://./ --2020-08-17 09:38:26-- http://./ Resolving . (.)... 209.216.230.240 Connecting to . (.)|209.216.230.240|:80... connected. HTTP request sent, awaiting response... 400 Bad Request 2020-08-17 09:38:26 ERROR 400: Bad Request.

1f60c 6y ago

Does this mean you (theoretically) can’t name a host "dk" on your local network? That seems bad, (even if naming hosts after TLDs is a bad idea).

MayeulC 6y ago
Technically, you should be able to have your local host resolve first. To avoid it being resolved and use the TLD instead, use the trailing dot: http://dk./ http://dk./ https://news.ycombinator.com./ https://news.ycombinator.com./ This makes it a FQDN, just like you enter it in your DNS records. Practically, people tend to forget about it, and accessing websites this way sometimes break in unexpected ways when the server doesn't expect the trailing dot in the "host" header. http://www.dns-sd.org./TrailingDotsInDomainNames.html http://www.dns-sd.org./TrailingDotsInDomainNames.html
kevincox 6y ago
You shouldn't be doing this anyways. There are reserved TLDs for this like .corp https://tools.ietf.org/id/draft-chapin-rfc2606bis-00.html#new https://tools.ietf.org/id/draft-chapin-rfc2606bis-00.html#ne...

SuperCuber 6y ago

How does this work? Also, why can't nslookup resolve it?

zuppy 6y ago
domains are split by the dot, from right to left. what is not visible is that the top level domain is not really the first one. the first one is the root domain (or root zone), which is represented by an empty string. you can try it on any domain, add a dot at the end. it will resolve, but the web server may not be configured to respond to it with the right website. if you want to query a dns server for a top level domain, you have to query the dns that handles it, which in our case is one of the 13 root dns servers. read more here: https://en.m.wikipedia.org/wiki/DNS_root_zone https://en.m.wikipedia.org/wiki/DNS_root_zone https://en.m.wikipedia.org/wiki/Root_name_server https://en.m.wikipedia.org/wiki/Root_name_server

cryptonector 6y ago

Technically it could be shorter still, if only either . had an A RRset, or if there were 1-character TLDs. Just cause those aren't true today, doesn't mean they can't ever be true.