Mac Address Regex Java Validator

What is a MAC Address?

A MAC (Media Access Control) address is a unique hardware identifier assigned to network interfaces. A typical MAC address contains six groups of two hexadecimal digits, separated by either colons (:) or hyphens (-). Validating MAC addresses is essential in applications dealing with network configurations, IoT devices, and security monitoring.

Java Regex Pattern for MAC Address

"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$"

Explanation:

• ^ and $: Anchors to ensure the pattern matches the entire string

• ([0-9A-Fa-f]{2}[:-]){5}: Matches five groups of two hex characters followed by either : or -

• ([0-9A-Fa-f]{2}): Final group of two hex characters

• Accepts both formats: 01:23:45:67:89:AB and 01-23-45-67-89-AB

Java Code Example:

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class MacAddressValidator {
    public static void main(String[] args) {
        String mac = "00:1A:2B:3C:4D:5E";
        String regex = "^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$";

        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(mac);

        if (matcher.matches()) {
            System.out.println("Valid MAC address");
        } else {
            System.out.println("Invalid MAC address format");
        }
    }
}

Valid & Invalid Examples

Valid:

• 00:1A:2B:3C:4D:5E

• 01-23-45-67-89-ab

• FF:FF:FF:FF:FF:FF

  
  

Invalid:

• 001A2B3C4D5E (No separators)

• ZZ:23:45:67:89:AB (Invalid characters)

• 01:23:45:67:89 (Too short)

• 01:23:45:67:89:AB:CD (Too long)

Pro Tips

• Always sanitize user input before validating to avoid injection risks.

• Use consistent separators (either : or -) in your backend systems for clean database storage.

• MACs are hexadecimal; restrict input to 0–9 and A–F/a–f only.

• Test edge cases like broadcast MAC (FF:FF:FF:FF:FF:FF) or multicast addresses.

• Don’t confuse MAC addresses with IPs—MACs are static hardware-level identifiers.

• The regex only checks format, not whether the MAC exists or is active.

Where It’s Used

• Networking Software: Validate MACs in routers, switches, or DHCP tools

• Inventory Systems: Ensure consistent MAC formats in device databases

• IoT Applications: Track devices across hubs and ensure secure registration

• Security Monitoring: Detect spoofed or malformed MAC addresses in logs

Combine with These Tools

• IP Address Regex Java Validator: Validate IPs in the same network configuration.

• UUID Regex Java Validator: Validate unique identifiers for connected devices.

• Java Regex Tester: Experiment with variations of MAC address patterns.