Regular Expressions in Action
Matching IPv4 Addresses
# Simple regex to check for an IP address
^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$
# Accurate regex to check for an IP address
^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$
# Simple regex to extract IP addresses from longer text
\b(?:[0-9]{1,3}\.){3}[0-9]{1,3}\b
# Accurate regex to extract IP addresses from longer text
\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b
# Simple regex that captures the four parts of the IP address
^([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})\.([0-9]{1,3})$
# Accurate regex that captures the four parts of the IP address
^(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$
refer: