Unfortunately, dotless domains will not work as intended by TLD operators in the vast majority of cases. As recommended by IETF standards track RFCs, existing deployed systems apply a search list to single-label names prior to attempting to resolve them. As a result, the resolution of dotless domains depends on local configuration such as the search list. For example, in a location where “example.com” is included within the search list, the URL http://printer1/ will generate a query for “printer1.example.com”, whereas in a location where “example.net” is in the search list, it will generate a query for “printer1.example.net”.

This behavior was developed in the DNS precisely because most users entering single-label names want them to be resolved in a local context, and they do not expect a single name to refer to a TLD. The behavior is specified within a succession of standards track documents developed over several decades, and is now implemented by hundreds of millions of Internet hosts. This standard approach enables single-label names to be conveniently used as shortcuts to hosts within a local administration, while also shielding the root zone from a potentially excessive number of queries for single-label names. Since the configuration of the search list has security implications, it is under the control of local host and network administrators, and completely outside the control of TLD operators.

Since dotless domains will not behave consistently across various locations (and applications and platforms that may have different search list configuration mechanisms), they have the potential to confuse users and erode the stability of the global DNS. By attempting to change expected behavior, dotless domains introduce potential security vulnerabilities. These include causing traffic intended for local services to be directed onto the global Internet (and vice-versa), which can enable a number of attacks, including theft of credentials and cookies, cross-site scripting attacks, etc. As a result, the deployment of dotless domains has the potential to cause significant harm to the security of the Internet.

The IAB therefore feels compelled to state the following:

1. The IAB strongly recommends against considering, implementing, or deploying dotless domains.

2. The IAB believes that dotless domains are inherently harmful to Internet security.