What is the regex pattern for ipv4 address?

The regex pattern for ipv4 address is: ^(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)$.

How does the ipv4 address regex work?

^: Start of string. (?:25[0-5]|2[0-4]\d|[01]?\d\d?): Octet: 0-255. \.: Literal dot separator. {3}: Repeat first three octets with dots. (?:25[0-5]|2[0-4]\d|[01]?\d\d?): Fourth octet: 0-255. $: End of string.

Regex for IPv4 Address

Matches valid IPv4 addresses (0.0.0.0 to 255.255.255.255) with proper octet range validation.

Pattern

/^(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)$/

Pattern Breakdown

Token	Explanation
^	Start of string
(?:25[0-5]\|2[0-4]\d\|[01]?\d\d?)	Octet: 0-255
\.	Literal dot separator
{3}	Repeat first three octets with dots
(?:25[0-5]\|2[0-4]\d\|[01]?\d\d?)	Fourth octet: 0-255
$	End of string

Test Examples

Input	Match?
192.168.1.1	Match
0.0.0.0	Match
255.255.255.255	Match
256.1.1.1	No match
192.168.1	No match

Common Use Cases

Network configuration validation
Firewall rule input
Log parsing
Server configuration

Variations

\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b

Simpler (no range validation)

Other Regex Patterns

Email Address US Phone Number International Phone Number URL IPv6 Address Date (MM/DD/YYYY)Date (ISO 8601 YYYY-MM-DD)Time (HH:MM, 24-hour)Credit Card Number US Social Security Number US ZIP Code Hex Color Code

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