A fully qualified domain name (FQDN) is the complete address of an internet host or computer. It provides its exact location within the domain name system (DNS) by specifying the hostname, domain name and top-level domain (TLD). For example, for the domain name www.whatis.com, "www" is the hostname, "whatis" is the domain name and ".com" is the top-level domain. Show
DNS filtering and network rules can be added to firewalls to allow or deny traffic to specific computers or domains. Are FQDN and URL the same?In internet communications, the terms FQDN and URL are sometimes used interchangeably. However, an FQDN isn't the same as a URL but rather is a part of it that fully identifies the server to which the request is addressed. An FQDN doesn't carry the TCP/IP protocol information -- such as Hypertext Transfer Protocol (HTTP) or Hypertext Transfer Protocol Secure (HTTPS) -- which is always used at the beginning of a URL. Therefore, adding the prefix http:// or https:// to the FQDN turns it into a full URL. Also, URLs can specify directory paths, file names and TCP port numbers, which FQDNs don't include. When FQDNs are provided in place of full URLs to access resources on the internet, the protocol by default is assumed to be HTTP or HTTPS. Examples of an FQDNFor a device to be accessible on the internet, it needs a fully qualified domain name. For an FQDN to be complete, it must meet the following criteria:
An FQDN is always labeled in the format of hostname.domain.TLD. For example, a mail server on the yahoo.com domain might use the FQDN mail.yahoo.com. The following are some examples of an FQDN:
Note that each label -- including hostname, domain name and TLD -- is separated by a period and ends with a trailing period. However, most systems simply imply the period, even if one isn't provided. For example, DNS servers consider www.microsoft.com an FQDN. Why and when to use an FQDNEach device on the internet has an Internet Protocol (IP) address and a corresponding FQDN. FQDNs reveal the absolute domain name of a site and prove useful when troubleshooting DNS issues. The following are popular use cases for FQDNs:
How to find an FQDNFQDN use isn't limited to the internet, but each PC and server has its own FQDN. It's easy to find the FQDN of any device, depending on which operating system is being used. Finding the FQDN for Windows 11Use the following steps to find an FQDN for Windows 11:
Finding the FQDN for macOSUse the following steps to find an FQDN for macOS:
Alternatively, in macOS, opening the terminal and typing hostname -f into the prompt returns the FQDN. For Linux, opening the terminal and entering hostname -A, where the A is case-sensitive, into the prompt returns the FQDN. What is a partially qualified domain name (PQDN)?A PQDN is part of an FQDN that isn't fully specified. In general, a PQDN gives an incomplete piece of information regarding where a resource is located on the internet or on a private server. For example, a hostname of p402srv01 is classified as a PQDN, because it only tells the hostname. The domain that it belongs to is unknown. PQDNs are typically used for convenience and are applicable where the full name isn't required to resolve the host, as the domain might already be known elsewhere. In those special scenarios, only the hostname is required for a particular task. To understand the difference between a PQDN and an FQDN, think of a phone number, where the PQDN is the three-digit area code and the FQDN is the 10-digit phone number. The process of name resolution plays an integral role in network communications. Learn how the name resolution process is used for resolving hostnames, querying servers and locating IP addresses. This was last updated in December 2022 Continue Reading About fully qualified domain name (FQDN)
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Was bedeutet Fully Qualified Domain Name?Was ist der Fully Qualified Domain Name (FQDN)? Mit dem Begriff „Fully Qualified Domain Name“ oder abgekürzt „FQDN“ wird der vollständige und eindeutige Hostname einer Webpräsenz im Internet bezeichnet. Er ist Teil des Domain Name Systems (DNS), das zur Namensauflösung im Internet verwendet wird.
Wie viele Zeichen kann ein voll qualifizierter Domainname Fully Qualified Domain Name FQDN enthalten?Zwischen dem Label des Hostnamens und dem Label des Domain-Namens können in einem Fully-Qualified Domain Name ein oder mehrere Label für Subdomains enthalten sein. Ein einzelnes Label darf aus bis zu 63 Zeichen bestehen. Die komplette Länge eines FQDN ist auf 255 Zeichen begrenzt.
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