Host Networking

Docker Host Networking

Host networking removes network isolation between container and host.

When to Use Host Networking

Basic Usage

# Run with host networking
docker run --network host nginx

# Container sees host's network interfaces
docker run --network host alpine ip addr

Implications

What Changes

# Port mapping is ignored with host network
docker run --network host -p 8080:80 nginx  # -p is ignored

# Container uses host's localhost
docker run --network host alpine curl localhost:80

Security Considerations

• Container can access all host network interfaces
• No port isolation
• Container can bind to any port
• Not recommended for untrusted workloads

Docker Compose

version: '3.8'
services:
  app:
    image: myapp
    network_mode: host
    # ports: ignored with host mode

Performance Comparison

Limitations

# Host networking only works on Linux
# On macOS/Windows, containers run in a VM
# so "host" refers to the VM, not your machine

Monitoring with Host Mode

# Perfect for network monitoring tools
docker run --network host \
  -v /var/run/docker.sock:/var/run/docker.sock \
  nicolaka/netshoot

# Access Prometheus node exporter
docker run --network host prom/node-exporter

Best Practices