IP Address Regex Go Validator

Introduction: What Is an IP Address Regex?

In Go, regular expressions (regex) offer a powerful way to validate patterns like IP addresses. IPs are fundamental in any network-based system—whether you’re storing user info, configuring firewalls, or building web applications.

IP addresses come in two types:

• IPv4 (e.g., 192.168.1.1)

• IPv6 (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334)

  
  

IP Address Regex Patterns

IPv4 Regex Pattern

^(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}$

Explanation:

• Validates 4 octets separated by dots.

• Each octet ranges from 0 to 255.

• Example match: 192.168.0.1

  
  

IPv6 Regex Pattern

^([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}$

Explanation:

• Matches 8 groups of hexadecimal numbers separated by colons.

• Each group has 1–4 hex digits.

• Example match: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

How to Validate IPs in Go Using Regex

Use Go’s built-in regexp package to compile the pattern and test strings:

package main

import (
    "fmt"
    "regexp"
)

func isValidIPv4(ip string) bool {
    ipv4Pattern := `^(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}$`
    regex := regexp.MustCompile(ipv4Pattern)
    return regex.MatchString(ip)
}

func isValidIPv6(ip string) bool {
    ipv6Pattern := `^([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}$`
    regex := regexp.MustCompile(ipv6Pattern)
    return regex.MatchString(ip)
}

func main() {
    testIPs := []string{
        "192.168.1.1",                    // valid IPv4
        "256.300.88.1",                   // invalid IPv4
        "2001:0db8:85a3:0000:0000:8a2e:0370:7334", // valid IPv6
        "2001:db8::1",                    // invalid (compressed, unsupported here)
    }

    for _, ip := range testIPs {
        fmt.Printf("IP: %s | IPv4: %t | IPv6: %t\n", ip, isValidIPv4(ip), isValidIPv6(ip))
    }
}

Use Cases of IP Address Regex Validation

• User IP Tracking: Validate IPs before storing them in logs or analytics tools.

• Access Control: Only allow requests from whitelisted IP ranges.

• Network Configuration: Automate validation of IPs during setup or provisioning.

• Data Cleanup: Standardize datasets with malformed or corrupted IP records.

  
  

Pro Tips

• Use IPv6 validation only when required, as many systems still rely primarily on IPv4.

• Regex doesn’t validate reserved or local IPs (like 127.0.0.1 or ::1)—only format.

• When working with compressed IPv6 formats (like ::1), consider using the net package for full parsing.

• Use Go Regex Tester to fine-tune your IP patterns and test edge cases.

  
  

Combine with These Tools

Use the IP Address Regex Go Validator in workflows that also require:

• Password Regex Go Validator – Secure user credentials

• Email Regex Go Validator – Validate contact data with IPs

• URL Regex Go Validator – Check URLs tied to IPs

• Go Regex Tester – Test your IP patterns directly

• GUID Regex Go Validator – Validate resource identifiers