In visiting http://to./ you are given a legitimate website.
Is to. a valid domain name then, despite not ending with a TLD and having a superfluous period? Why?
Being valid, what would its DNS hierarchy be?
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156answers:
2
+12
A:
to is the TLD of Tonga.
There is no spec that says that a domain name must have something other than a TLD; Tonga is the only TLD that has an A record for the TLD itself.
However, most browsers will not recognize a domain name that doesn't contain a period, so they use the full FQDN, with a trailing ..
SLaks
2010-04-21 15:10:23
Not a satisfying explanation for the dot *after* the to - which is not superfluous, http://to/ does not work.
Michael Borgwardt
2010-04-21 15:12:11
Yes, we need more explanation. I'm getting a "TO./ URL Shortener" service site.
zaf
2010-04-21 15:15:12
The `.` at the end forces the browser to realize that it's a domain name.
SLaks
2010-04-21 15:19:22
@Michael: Your link to http://to works just fine in Google Chrome, for example.
Henning
2010-04-21 15:19:35
http:// to / works for me, as does http:/ /www.google.co m./ (shame SO's formatting breaks the link :P)
Matt
2010-04-21 15:20:47
@Henning As I'm using a web proxy config script, my browser attempts to open `to.lancs.ac.uk` when I request `to`.
Beau Martínez
2010-04-21 15:25:32
a trailing . denotes the root of the hierarchy - it's not mandatory though. Without it, typical dns resolvers will prepend the local domain name if the name has only 1 component, and try a lookup of e.g. http://to.mycompany.com/ first.
nos
2010-04-21 15:30:32
+13
A:
The final dot is part of the fully qualified domain name. More information in this article. Specifically:
It's a little-known fact, but fully-qualified (unambiguous) DNS domain names have a dot at the end. People running DNS servers usually know this (if you miss the trailing dots out, your DNS configuration is unlikely to work) but the general public usually doesn't. A domain name that doesn't have a dot at the end is not fully-qualified and is potentially ambiguous.
Toon Van Acker
2010-04-21 15:16:53