You tried to connect to Ollama and got:

Connection refused: http://localhost:11434

Here is how to fix it.

Fix 1: Start Ollama server

Ollama runs as a background service. Start it:

# Start Ollama server
ollama serve

# Or run in background
nohup ollama serve &

On macOS, Ollama runs automatically when installed. Check if it is running:

curl http://localhost:11434
# Should return: Ollama is running

Fix 2: Check port

Ollama defaults to port 11434. If it is in use:

# Check what's using port 11434
lsof -i :11434  # macOS
netstat -tlnp | grep 11434  # Linux

# Kill conflicting process
kill -9 <PID>

Or use a different port:

OLLAMA_HOST=0.0.0.0:11435 ollama serve

Fix 3: Fix Docker networking

If Ollama runs in Docker:

services:
  ollama:
    image: ollama/ollama
    ports:
      - "11434:11434"  # Expose port

Then connect to http://localhost:11434 from your host.

For Docker-to-Docker communication:

services:
  app:
    # Connect to ollama service name, not localhost
    environment:
      - OLLAMA_URL=http://ollama:11434

Fix 4: Fix firewall

Firewall may block port 11434:

# Linux (UFW)
sudo ufw allow 11434/tcp

# Linux (firewalld)
sudo firewall-cmd --add-port=11434/tcp --permanent
sudo firewall-cmd --reload

# macOS: Check System Preferences > Security & Privacy > Firewall

Fix 5: Check Ollama is listening on all interfaces

By default, Ollama only listens on localhost:

# Listen on all interfaces (for remote access)
OLLAMA_HOST=0.0.0.0:11434 ollama serve

Fix 6: Check network configuration

If connecting remotely:

# Test connectivity
ping <server-ip>

# Test port
telnet <server-ip> 11434

# Or with nc
nc -zv <server-ip> 11434

Fix 7: Restart Ollama

# Kill existing Ollama
pkill ollama

# Start fresh
ollama serve

Still not working?

1. Check Ollama logs — OLLAMA_DEBUG=1 ollama serve
2. Reinstall Ollama — Sometimes a clean install fixes networking issues
3. Check Docker logs — docker logs ollama
4. Try different port — Some networks block default ports

FAQ

What port does Ollama use?

Ollama uses port 11434 by default. You can change it with OLLAMA_HOST=0.0.0.0:PORT ollama serve. Check your configuration if you are using a different port.

How do I know if Ollama is running?

Run curl http://localhost:11434. If it returns “Ollama is running”, the server is up. If you get “connection refused”, Ollama is not running or is listening on a different port.

Can I access Ollama from another machine?

Yes, but you need to set OLLAMA_HOST=0.0.0.0:11434 to listen on all interfaces, and ensure your firewall allows port 11434. See our Ollama Complete Guide for network setup details.

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