Regex for IP Addresses: Match IPv4 and IPv6
Match IPv4 and IPv6 addresses with accurate regex. Avoid the common overmatch trap and validate octets are within 0–255 range correctly.
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Tags: developer-tools, regex, networking
Regex for IP Addresses: Match IPv4 and IPv6 With Accurate Patterns IP address validation sounds simple until you try it. A naive regex like matches , which is not a valid IPv4 address. A correct regex needs to constrain each octet to 0–255. IPv6 adds a new layer of complexity with its 8-group hex format and multiple shorthand notations. This article gives you accurate, tested patterns for both. --- IPv4: The Right Pattern IPv4 addresses are four octets separated by dots. Each octet is a decimal number from 0 to 255. The Wrong Pattern (Don't Use This) This is the most commonly copy-pasted IPv4 pattern, and it's wrong. It matches: (each octet max is 255, not 999) (256 is out of range) (debatable, but leading zeros can cause octal interpretation in some systems) The Correct Pattern Each…
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