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It is possible to get a generic TLD, such as .example. A DNS search for example would go though the root servers, which would find a glue record for example and forward the request to the designated NS. This is not different from .com or others.

This means that I can gave email addresses such as hello@example and host a web site at example.

How are such bare names resolved on clients (clients to DNS, these can be servers or actual end user machines)?

  • a Linux server server.foo.com with a typical resolution would append to such a bare query the domain it is on - assuming that the request is for a host on its domain. It would then request the resolution of example.foo.com, which is not what is expected

  • I believe the same would happen with a Windows server (?)

  • on the end user side, typing in example in e.g. Chrome will trigger a search of the word example, as it is missing a full, dotted address

WoJ
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  • Not very well. Many software packages assume that a name with only one label is not fully qualified. Related: [DNS just started resolving my server.prod addresses to 127.0.53.53](https://serverfault.com/q/626612/126632) – Michael Hampton Jan 28 '18 at 14:03
  • Specify a protocol and a single name can work, IF there is a hosts file entry or DNS available to resolve it - `http://example` works in my Chrome just fine - my `search domain` in resolv.conf isn't set – ivanivan Jan 28 '18 at 15:02
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    Note that this is a purely theoretical question. The agreement with ICANN that you'd have to sign to get your gTLD specifies that you must not have A or MX records for the top-level name (once it has gone properly live, as in the question linked above, for a period before it goes live it gets an A with address 127.0.53.53 as a flag that the name is about to start existing). – Calle Dybedahl Jan 29 '18 at 14:29
  • @CalleDybedahl: thank you , I didn't know that I just tested the `ovh` domain and it responnds with a `SOA` but indeed no `A`or `MX`on the root level. – WoJ Jan 29 '18 at 15:20

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It is technically possible, and some registries publish A or MX records directly at the TLD level. For example dig A ws. +short will get you 64.70.19.33 and you have an MX record too: mail.worldsite.ws

Some are speculating that the rush into new gTLDs is, at least in part, due to people thinking that by having such TLD they would have been able to have emails directly @tld and a website like http://TLD/. Imagine if TLD = SEARCH for example.

It would have been basically the rebirth of the concept of keywords that were all the rage long ago, when promoted as concurrent to the domain name space.

This would have created, among other things, a lot of problems on the web due to cookies and the way that there is currently no automated mechanisms for browsers to find administrative cuts (since they do not fell perfectly on the DNS "dot" separator). Same for WPAD DNS auto-discovery and various other mechanisms were applications walk the DNS tree up the root.

Nevertheless it more often than not does not work as expected, mostly due to default configurations. Systems are configured with a search list, so that when you use a name somewhere it is also tried with various suffixes. This list can be fixed or even retrieved by DHCP.

Also, ICANN restrictions (in the registries contracts) prohibit basically everything at the apex of the TLD, besides SOA, NS, DS, and RRSIG records (for the main ones). But that impacts only gTLDs as ccTLDs are not in a contract with ICANN and are free to do what they want on that point(!).

You had a lot of discussions, reports and resolutions around these "dotless" domains, see https://features.icann.org/dotless-domains and especially the technical report: https://www.icann.org/en/system/files/files/sac-053-en.pdf which was followed by an IAB report: https://www.iab.org/2013/07/10/iab-statement-dotless-domains-considered-harmful/

This article is a good summary: http://www.circleid.com/posts/20130711_the_missing_link_in_dotless_domains/

And for many technical details: https://labs.apnic.net/?p=429 with studies on various resolvers on various OSes.

Patrick Mevzek
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