How to Detect Proxies on Your Website
(PHP, Node.js, Go Examples)

Table of Contents

• Why Detect Proxies?
• Method 1: Checking Headers
• Method 2: Using IP Intelligence API
• Code Snippets

Why Detect Proxies?

Proxies are intermediaries. While used for privacy, they are the primary tool for bad actors to bypass IP bans, rate limits, and geo-restrictions.

Method 1: Checking Headers

Some "transparent" proxies leak their presence via HTTP headers. You can check for:

• HTTP_VIA
• HTTP_X_FORWARDED_FOR
• HTTP_FORWARDED

Note: Elite/Anonymous proxies strip these headers, so this method is only 20% effective.

Method 2: Using IP Intelligence API

The only robust way is to check the IP against a database of known proxy exit nodes.

Code Snippets

PHP

$ip = $_SERVER['REMOTE_ADDR'];
$json = file_get_contents("https://api.ipasis.com/v1/lookup?ip={$ip}&key=YOUR_KEY");
$data = json_decode($json, true);

if ($data['is_proxy'] === true) {
    die("Access Denied: Proxy Detected");
}

JavaScript (Node.js)

const https = require('https');

https.get(`https://api.ipasis.com/v1/lookup?ip=${req.ip}`, (res) => {
    let data = '';
    res.on('data', (chunk) => { data += chunk; });
    res.on('end', () => {
        const result = JSON.parse(data);
        if (result.is_proxy) {
            console.log("Proxy blocked");
        }
    });
});

FAQs