How to fix Error: connect ENETUNREACH 10.0.0.1:443 in Node.js

Node.jsINTERMEDIATEMEDIUM

The ENETUNREACH error occurs when Node.js cannot establish a network connection because the destination network is unreachable. This typically indicates routing problems, network interface issues, or firewall restrictions preventing your application from reaching the target host.

What this error means

The ENETUNREACH (Error Number 101) error is a low-level network error that occurs when the operating system's networking stack determines that no route exists to reach the destination network. This is different from a connection timeout or refused connection - the system knows immediately that it cannot even attempt to reach the target. When Node.js makes a network request using modules like `http`, `https`, `axios`, or `fetch`, it relies on the underlying operating system to establish the connection. If the OS cannot find a valid network path to the destination IP address or subnet, it returns the ENETUNREACH error. This error commonly appears in containerized environments (Docker, Kubernetes), when using VPNs, during network configuration changes, or when attempting to connect to private/internal networks from an isolated context.

How to fix "Error: connect ENETUNREACH 10.0.0.1:443"

1Verify the target IP address and network connectivity

First, confirm that the IP address you're trying to reach is correct and that basic network connectivity exists:

bash

# Ping the target IP
ping 10.0.0.1

# Check if the IP is reachable
traceroute 10.0.0.1

# Verify your network interfaces are up
ip addr show
# or on older systems
ifconfig

If ping fails with "Network is unreachable", the problem is at the routing level, not specific to Node.js.

2Check routing table for destination network

Examine your system's routing table to see if a route exists for the destination network:

bash

# On Linux/Mac
ip route show
# or
route -n

# On Windows
route print

Look for a route that matches the destination network. If missing, you may need to add a route:

bash

# Add a route (requires sudo)
sudo ip route add 10.0.0.0/24 via 192.168.1.1 dev eth0

Replace 10.0.0.0/24 with your destination network, 192.168.1.1 with your gateway, and eth0 with your network interface.

3Fix Docker network configuration conflicts

If you're running Node.js in a Docker container and experiencing this error, the issue often relates to network isolation or subnet conflicts:

Option 1: Use host network mode (removes network isolation)

yaml

# docker-compose.yml
services:
  app:
    image: node:18
    network_mode: "host"

Option 2: Configure Docker default address pools to avoid VPN/network conflicts:

json

// /etc/docker/daemon.json
{
  "default-address-pools": [
    {
      "base": "172.17.0.0/12",
      "size": 24
    }
  ]
}

After modifying daemon.json, restart Docker:

bash

sudo systemctl restart docker

Option 3: Add route inside container (if you need specific network access):

dockerfile

# In your Dockerfile
RUN ip route add 10.0.0.0/24 via 172.17.0.1

4Enable IP forwarding on the host

If containers need to reach external networks, ensure IP forwarding is enabled on the host:

bash

# Check if IP forwarding is enabled
sysctl net.ipv4.ip_forward

# Enable IP forwarding temporarily
sudo sysctl -w net.ipv4.ip_forward=1

# Enable permanently by editing /etc/sysctl.conf
echo "net.ipv4.ip_forward=1" | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

For IPv6:

bash

sudo sysctl -w net.ipv6.conf.all.forwarding=1

5Handle the error gracefully in your Node.js code

Implement proper error handling to catch and handle ENETUNREACH errors:

javascript

const http = require('http');

const options = {
  hostname: '10.0.0.1',
  port: 443,
  method: 'GET'
};

const req = http.request(options, (res) => {
  console.log(`Status: ${res.statusCode}`);
});

req.on('error', (err) => {
  if (err.code === 'ENETUNREACH') {
    console.error('Network unreachable. Check routing and network configuration.');
    console.error(`Target: ${err.address}:${err.port}`);

    // Implement fallback logic
    // - Try alternative endpoint
    // - Queue request for retry
    // - Use cached data
  } else {
    console.error('Request failed:', err);
  }
});

req.end();

With axios:

javascript

const axios = require('axios');

try {
  const response = await axios.get('http://10.0.0.1:443');
} catch (error) {
  if (error.code === 'ENETUNREACH') {
    console.error('Network unreachable:', error.message);
    // Handle gracefully
  }
  throw error;
}

6Verify firewall rules

Check if firewall rules are blocking traffic to the destination network:

On Linux (iptables):

bash

# View all iptables rules
sudo iptables -L -n -v

# Check if there are DROP or REJECT rules for your destination
sudo iptables -L OUTPUT -n -v | grep 10.0.0.1

On Linux (firewalld):

bash

# Check firewall status
sudo firewall-cmd --state

# List all rules
sudo firewall-cmd --list-all

On macOS:

bash

# Check if pf firewall is blocking
sudo pfctl -s rules

If needed, add firewall rules to allow the traffic, but ensure you understand the security implications.

How to fix Error: connect ENETUNREACH 10.0.0.1:443 in Node.js

What this error means

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How to fix "Error: connect ENETUNREACH 10.0.0.1:443"

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