How to fix Error: EHOSTDOWN: host is down in Node.js

# Ping the target host
ping example.com

# Check TCP connectivity on the specific port
telnet example.com 80

# Or use nc (netcat)
nc -zv example.com 80

const http = require('http');

const options = {
  hostname: 'example.com',
  port: 80,
  path: '/',
  method: 'GET'
};

const req = http.request(options, (res) => {
  // Handle response
});

req.on('error', (err) => {
  if (err.code === 'EHOSTDOWN') {
    console.error('Host is down:', err.message);
    // Implement retry logic or fallback
  } else {
    console.error('Request error:', err);
  }
});

req.end();

const axios = require('axios');

try {
  const response = await axios.get('http://example.com');
} catch (error) {
  if (error.code === 'EHOSTDOWN') {
    console.error('Host is down, retrying with backup server...');
    // Implement fallback logic
  } else {
    throw error;
  }
}

# For AWS SSO users, refresh your session
aws sso login --profile your-profile

# Or re-configure credentials
aws configure

const AWS = require('aws-sdk');

// Explicitly set credentials with error handling
AWS.config.credentials = new AWS.SharedIniFileCredentials({
  profile: 'your-profile'
});

AWS.config.credentials.get((err) => {
  if (err) {
    console.error('Error loading credentials:', err);
  } else {
    console.log('Credentials loaded successfully');
  }
});

async function fetchWithRetry(url, maxRetries = 3, baseDelay = 1000) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      const response = await fetch(url);
      return response;
    } catch (error) {
      if (error.code === 'EHOSTDOWN' && attempt < maxRetries) {
        const delay = baseDelay * Math.pow(2, attempt - 1);
        console.log(`Attempt ${attempt} failed, retrying in ${delay}ms...`);
        await new Promise(resolve => setTimeout(resolve, delay));
      } else {
        throw error;
      }
    }
  }
}

// Usage
try {
  const result = await fetchWithRetry('http://example.com/api');
} catch (error) {
  console.error('All retry attempts failed:', error);
}

# Check local firewall (Linux)
sudo iptables -L -n

# Check if SELinux is blocking (RHEL/CentOS)
sudo getenforce
sudo ausearch -m avc -ts recent

# Verify DNS resolution
nslookup example.com
dig example.com

# Check routing table
netstat -rn
# or
ip route show

// Set proxy for Node.js HTTP requests
const https = require('https');
const HttpsProxyAgent = require('https-proxy-agent');

const agent = new HttpsProxyAgent('http://proxy.company.com:8080');

https.get('https://example.com', { agent }, (res) => {
  // Handle response
});