ShareYourGroupShareYourGroupSubnet and Ports

Subnetting, IPv6 and port guides

8 guides with worked examples that were checked by program.

Where to start

New to networks? Read "What is subnetting", then "How to subnet step by step" and try the calculator. For IPv6, start with "IPv4 and IPv6 compared", then the address format page. For ports, read "What is a port number" and then the topic pages.

This is an independent guide. It is not connected with IANA, the IETF or any network equipment maker. Address and port data come from the IANA registries as fetched on 14 November 2026; RFC texts were read from rfc-editor.org. Check the originals for anything you rely on.