What's Actually Happening

Clients cannot connect to NATS server. Connection attempts are refused.

The Error You'll See

go
nats: no servers available for connection

Why This Happens

  1. 1.Server not running - NATS process stopped
  2. 2.Wrong port - Client connecting to wrong port
  3. 3.Firewall blocking - Port blocked by firewall
  4. 4.Bind address - Server not listening on expected interface

Step 1: Check Server Status

```bash # Check if NATS running: ps aux | grep nats

# Or with systemd: systemctl status nats

# Check port: netstat -tlnp | grep 4222 ```

Step 2: Start Server

```bash # Start NATS: nats-server &

# Or with systemd: systemctl start nats ```

Step 3: Test Connection

```bash # Test with telnet: telnet localhost 4222

# Or with nats CLI: nats server info ```

Step 4: Check Configuration

```bash # Check config: cat nats.conf

# Verify port: grep port nats.conf

# Start with config: nats-server -c nats.conf ```

NATS Connection Checklist

CheckCommandExpected
Server runningps auxRunning
Port listeningnetstat4222
FirewalliptablesAllowed

Verify the Fix

bash
nats server info
# Output: Server info displayed
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