Add QFDN / PFDN to glossary

[pavelloz]

A  Fully Qualified Domain Name (or FQDN) is a complete and unambiguous domain name that specifies an exact location for an object in a Domain Name System (DNS) hierarchy. It specifies all domain levels, including the top-level domain and the root zone. Most domain names as used in the internet’s Uniform Resource Locators (or URL) are only partially qualified (but work just fine).

A fully qualified domain name can be interpreted only in one way – it is a completely unique address for one and only one location.

## FQDN Examples

A fully qualified domain name is always written in this format: [hostname].[domain].[tld]. For example, a mail server on the example.com domain may use the FQDN mail.example.com.

Here are some other examples of fully qualified domain names:

www.microsoft.com
en.wikipedia.org
p301srv03.timandtombreadco.us


### PQDN

A Partially Qualified Domain Name (PQDN) is used to specify a portion of a domain name, normally the host portion of it. A Partially Qualified Domain Name (PQDN) starts with a host name, but it may not reach up to the root.

Example of Partially Qualified Domain Name (PQDN) pc15. Usually the computers will add the DNS suffix along with Partially Qualified Domain Name (PQDN) before sending a DNS query for name resolution.

Sources:
https://www.lifewire.com/what-does-fqdn-mean-2625883
https://www.ssl.com/faqs/what-is-a-fully-qualified-domain-name/
https://www.omnisecu.com/tcpip/fully-qualified-domain-name-fqdn-and-partially-qualified-domain-name-pqdn.php