What is a top-level domain or TLD?

The suffix of a domain name is known as a Tdl or a top level domain. It is used to identify the type of content of the particular website that is based on various types of organization such as .com, .edu, .name, .museum etc.

They can also be used as country codes to the type of website such as .in, .uk, .jp etc.

The tld or the top level domain is at the top of the hierarchy and is normally the last part of an internet domain name. These names are not case sensitive.

The top level domains are broadly classified into three types by the Internet assigned numbers authority or the IANA.

The first type relates to the country or territory of the website and and is know as country code related top level domains or the ccTLD. This pertains to the area and territory of a particular country in the last two letters. For eg. .jp would mean japan.

The second type is called the generic top level domains or gTLD which is used for a particular class of organizations. The most common of this type is .com which is used for all commercial organizations. All the gTLD’s are available for use worldwide but .gov and .mil are restricted to be used only in the United States by their respective authorities. The gTLD’s are further classified into sponsored top level domains sTLDs like .aero, .coop and un sponsored top level domains like .biz, .info.

The Third rare type of TLDs is known to be infrastructure top level domains. .apra is the only confirmed iTLD .However, .root are also known to exist without a reason.

The internet was in the past one of the many wide area networks that was available. The computers were not broadly connected to internet but were connected to each other through various sub networks and they could exchange data and email through the various gateways. When these networks were brought together and placed into the internet, these networks were given pseudo domains how ever these were not top level domains and did not exist in the DNS. Most of these networks have now long since ceased to exist and now can only be viewed as internet relics of the past.

The anonymity network aslo known as tor makes use of the pseudo domain onion. It can be only reached with a tor client which uses a tor protocol or onion routing that is used to reach the hidden services of the network. This is done in order to protect the anonymity of this network.