root@generate-random:~/ip-addresses/php$ _

Generate Random IP Addresses in PHP

Complete code tutorial with examples and best practices

PHP

[ Code Example - Quick Summary ]

Language: PHP

What: Generate random IPv4 and IPv6 addresses in PHP for network testing, API mocking, and development. This guide covers public/private IP ranges, CIDR notation, and validation.

Try it: Use our interactive Ip-addresses generator or integrate this code into your PHP application.

Generate random IPv4 and IPv6 addresses in PHP for network testing, API mocking, and development. This guide covers public/private IP ranges, CIDR notation, and validation. Looking for other languages? Check our code examples in JavaScript , Python , Java , C# , C++ , Ruby and Go or use our interactive web generator.

PHP Code Example

<?php
// Generate random IPv4 address
function randomIpv4() {
    return sprintf(
        "%d.%d.%d.%d",
        mt_rand(0, 255),
        mt_rand(0, 255),
        mt_rand(0, 255),
        mt_rand(0, 255)
    );
}

// Generate random private IPv4 (RFC 1918)
function randomPrivateIpv4() {
    $ranges = [
        ["10", mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255)],
        ["172", mt_rand(16, 31), mt_rand(0, 255), mt_rand(0, 255)],
        ["192", "168", mt_rand(0, 255), mt_rand(0, 255)],
    ];
    $ip = $ranges[array_rand($ranges)];
    return implode(".", $ip);
}

// Generate random public IPv4 (avoiding private ranges)
function randomPublicIpv4() {
    do {
        $ip = randomIpv4();
    } while (
        preg_match("/^10\./", $ip) ||
        preg_match("/^172\.(1[6-9]|2[0-9]|3[01])\./", $ip) ||
        preg_match("/^192\.168\./", $ip) ||
        preg_match("/^127\./", $ip) ||
        preg_match("/^0\./", $ip)
    );
    return $ip;
}

// Generate random IPv6 address
function randomIpv6() {
    $parts = [];
    for ($i = 0; $i < 8; $i++) {
        $parts[] = sprintf("%04x", mt_rand(0, 0xFFFF));
    }
    return implode(":", $parts);
}

// Generate IPv4 with CIDR notation
function randomIpv4WithCidr($minCidr = 8, $maxCidr = 32) {
    $ip = randomIpv4();
    $cidr = mt_rand($minCidr, $maxCidr);
    return "$ip/$cidr";
}

// Validate IPv4 address
function isValidIpv4($ip) {
    return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4) !== false;
}

// Validate IPv6 address
function isValidIpv6($ip) {
    return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) !== false;
}

// Generate multiple IP addresses
function generateIpAddresses($count = 10, $type = "ipv4") {
    $ips = [];
    for ($i = 0; $i < $count; $i++) {
        $ips[] = $type === "ipv6" ? randomIpv6() : randomIpv4();
    }
    return $ips;
}

// Usage examples
echo "Random IPv4: " . randomIpv4() . "\n";
echo "Private IPv4: " . randomPrivateIpv4() . "\n";
echo "Public IPv4: " . randomPublicIpv4() . "\n";
echo "IPv6: " . randomIpv6() . "\n";
echo "IPv4 with CIDR: " . randomIpv4WithCidr() . "\n";

$batch = generateIpAddresses(5);
echo "Batch: " . implode(", ", $batch) . "\n";

[EXPLANATION]

This implementation uses mt_rand() for generating random octets (0-255) and sprintf() for formatting IPv4 addresses. For private IPs, it follows RFC 1918 ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. IPv6 addresses use 8 groups of 4 hexadecimal digits. The filter_var() function with FILTER_VALIDATE_IP validates IP formats. CIDR notation adds a subnet mask (e.g., /24) for network testing.

Expected Output

Random IPv4: 198.51.100.42
Private IPv4: 192.168.15.234
Public IPv4: 203.0.113.89
IPv6: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
IPv4 with CIDR: 198.51.100.42/24
Batch: 203.0.113.15, 198.51.100.89, 192.0.2.45, 198.51.100.123, 203.0.113.67

Common Use Cases

Generate test IP addresses for network application testing
Mock API responses with realistic IP data
Create sample logs for security analysis and monitoring tools
Populate databases with network configuration test data
Test geolocation features with diverse IP addresses

Important Notes

filter_var() validates format but doesn't check if IP is reachable
RFC 1918 defines private IP ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
127.0.0.0/8 is reserved for loopback addresses
IPv6 can be compressed (e.g., 2001:db8::1) but this example shows full format
For production network testing, consider using test IP ranges like 192.0.2.0/24 (TEST-NET-1)