IPv4 Octet Extraction (Capture Groups) Regex for Go

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching ipv4 octet extraction (capture groups), ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// IPv4 Octet Extraction (Capture Groups)
// ReDoS-safe | RegexVault — Web & Network > IPv4

package validation

import "regexp"

var ipv4OctetExtractionCaptureGroupsRe = regexp.MustCompile(`^((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))$`)

func ValidateIpv4OctetExtractionCaptureGroups(s string) bool {
    return ipv4OctetExtractionCaptureGroupsRe.MatchString(s)
}

// Example
// fmt.Println(ValidateIpv4OctetExtractionCaptureGroups("192.168.1.1")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > IPv4 category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Groups 1–4 capture each octet as a string. Cast to integer after extraction. Python users can use (?P<octet1>...) syntax for named groups.