What is a Second-Level Domain?

In the network and domains topic, the term Second-Level-Domain is frequently mentioned. But what does it actually mean, what are the differences compared to the First-Level-Domain, and what is a Second-Level-Domain used for? These and other questions are answered in the following article.

What is a Second-Level-Domain?

The term Second-Level-Domain refers to the part of an internet address that directly precedes the Top-Level-Domain (such as ".de"). The Second-Level-Domain, which is the second level of the domain, identifies a name, a company, or a brand that uniquely distinguishes the operator of a website. For example, in the domain name hosttest.de, "hosttest" is the Second-Level-Domain.

The Second-Level-Domain is a subdomain and primarily serves to directly refer to the operator through the internet identifier. It is separated by a dot before and after from the Top-Level-Domain or the Third-Level-Domain. The uniqueness of the Second-Level-Domain in combination with the Top-Level-Domain and the Third-Level-Domain is determined by the fact that it can only be assigned once. It is used for identification, making it immediately clear to every user who operates a web address.

On the far right is the Root Label. It is the highest level in the DNS hierarchy and has an empty node name filled with a single octet of zeros. In the usual notation or in the browser, the Root Label is therefore omitted.

The next higher level in the DNS hierarchy is the Top-Level-Domain (also known as First-Level-Domain). This is the classic domain extension. In general, domain extensions are divided into two different Top Level Domains (TLDs): Generic Top Level Domains (gTLDs) and Country-Code Top Level Domains (ccTLDs).

The Second-Level-Domain represents the next higher level in the DNS hierarchy and represents the domain name itself. In contrast to the Top-Level Domain, this can be freely chosen (if the desired name is still available) and contributes to the unique identification on the Internet.

Finally, there are the Third-Level-Domain or Subdomains, which are used to determine the Internet protocols used or for the logical structuring of a website.

What to consider with the Second-Level-Domain?

Although the second-level domain can be freely chosen, there are a few points to consider here. Depending on the chosen top-level domain, there may be restrictions on the name selection. For example, special characters such as umlauts are available for a country-specific .de domain, while they may not be used in the desired name for an international top-level domain like the generic .com domain. Individual restrictions may exist not only in the availability of characters but also in the number of characters.

The risk when deciding on a second-level domain is clearly that when setting up the service by the domain provider, the internet address may be permanently lost. In direct comparison, the second-level domain often appears less professional. However, a logical structure, such as that of a company with subsidiaries or multiple branches, can be demonstrated with the help of the second-level domain. Here, visitors and signals from Google should be redirected to the current domain via a redirect, either 301 or 302.

Generally, it is advisable to keep a second-level domain as simple and precise as possible. This way, website visitors can easily remember the address and better associate it with the web content offered.

Find the right top-level domains for your web projects in the domain check or with one of the providers from the domain comparison on our website.

Secure the perfect desired name now: