Types of Docker Networks

1. Bridge Network:

   • The default network for Docker containers.
   • Ideal for standalone containers that need to communicate.
   • Containers on the same bridge network can communicate using their names as hostnames.
   • Example:

     sh
     docker network create my-bridge-network
     docker run -d --name container1 --network my-bridge-network nginx
     docker run -d --name container2 --network my-bridge-network nginx
     

   • Docker Docs - Network containers

2. Host Network:

   • Removes network isolation between the container and the Docker host.
   • Uses the host’s networking directly, making services available on the same IP as the host.
   • Example:

     sh
     docker run -d --name container3 --network host nginx
     

   • MTVLab - Docker Networking

3. Overlay Network:

   • Connects multiple Docker daemons together.
   • Enables swarm services to communicate with each other, essential for scaling applications.
   • Example:

     sh
     docker network create --driver overlay my-overlay-network
     

   • Docker Docs - Networking overview

4. Macvlan Network:

   • Assigns a MAC address to a container, making it appear as a physical device on your network.
   • Useful for legacy applications that require direct access to the physical network.
   • Example:

     sh
     docker network create -d macvlan --subnet=192.168.1.0/24 --gateway=192.168.1.1 -o parent=eth0 my-macvlan-network
     

5. None Network:

   • Disables all networking.
   • Useful for containers that do not need network access.

Advanced Networking Tips

• Static IP Assignments: Useful for services that require a fixed IP address.

  sh
  docker network connect --ip 172.18.0.22 my-bridge-network my-container
  

• Network Aliases: Allow multiple container names to resolve to the same container, simplifying service discovery.

  sh
  docker run -d --network=my-bridge-network --name my-service --network-alias service_alias alpine
  

• Port Mapping: Essential for making container services accessible outside the Docker host.

  sh
  docker run -d -p 80:80 --name web_server nginx
  

Best Practices

• Isolate Environments: Use separate networks for development, testing, and production environments to enhance security and reduce interference risks.
• Leverage DNS: Docker’s internal DNS simplifies service discovery within the same network.
• Monitor Network Traffic: Use tools like docker network inspect and third-party solutions to monitor traffic and diagnose issues.

Troubleshooting

• Connectivity Issues: Ensure containers are connected to the correct network and check firewall rules.
• DNS Problems: Verify that Docker’s internal DNS resolves container names correctly.
• Port Conflicts: Avoid conflicts by ensuring that host ports are not already in use when mapping.

For a more detailed exploration of Docker networking, you can refer to resources like the Docker Documentation and MTVLab's guide. These guides provide extensive insights and practical examples to help you master Docker networking.