How to fix Error: connect ENETUNREACH (no route to destination) in Node.js

# Ping the target host
ping example.com

# Check routing table
ip route show  # Linux
route print    # Windows
netstat -rn    # macOS

# Test TCP connection directly
telnet example.com 443
# or
nc -zv example.com 443

# Check VPN interface is up (Linux/macOS)
ifconfig | grep tun
ip addr show tun0

# Verify VPN routes are present
ip route | grep vpn

// Force IPv4 for HTTP requests
const https = require('https');

const options = {
  hostname: 'example.com',
  port: 443,
  path: '/',
  method: 'GET',
  family: 4  // Force IPv4
};

https.request(options, (res) => {
  // Handle response
}).end();

const axios = require('axios');

axios.get('https://example.com', {
  httpAgent: new (require('http').Agent)({ family: 4 }),
  httpsAgent: new (require('https').Agent)({ family: 4 })
});

npm config set registry https://registry.npmjs.org/
npm config set fetch-retries 3

# Set npm proxy
npm config set proxy http://proxy.company.com:8080
npm config set https-proxy http://proxy.company.com:8080

# Set environment variables for Node.js
export HTTP_PROXY=http://proxy.company.com:8080
export HTTPS_PROXY=http://proxy.company.com:8080

# For git operations via npm
git config --global http.proxy http://proxy.company.com:8080
git config --global https.proxy http://proxy.company.com:8080

npm config set proxy http://username:[email protected]:8080

# Linux: Check iptables rules
sudo iptables -L -n

# Check if specific port is allowed
sudo iptables -L OUTPUT -n | grep 443

# Temporarily disable firewall for testing (Linux)
sudo systemctl stop firewalld  # Fedora/CentOS
sudo ufw disable               # Ubuntu

# Use host network mode
docker run --network host your-image

# Or ensure bridge network has proper routing
docker network inspect bridge

services:
  app:
    image: node:18
    network_mode: "host"
    # or
    dns:
      - 8.8.8.8
      - 8.8.4.4

sudo systemctl restart docker

const https = require('https');

function requestWithRetry(options, maxRetries = 3) {
  return new Promise((resolve, reject) => {
    let attempts = 0;

    function attempt() {
      attempts++;

      const req = https.request(options, (res) => {
        resolve(res);
      });

      req.on('error', (err) => {
        if (err.code === 'ENETUNREACH' && attempts < maxRetries) {
          console.log(`Retry attempt ${attempts} after ENETUNREACH`);
          setTimeout(attempt, 1000 * attempts); // Exponential backoff
        } else {
          reject(err);
        }
      });

      req.end();
    }

    attempt();
  });
}