๐Ÿ“ Docker Networking Explained: How Containers Communicate in DevOps

Devops ankit sharma November 29, 2025 2 mins read

Understand Dockerโ€™s networking modes, container communication, and how to isolate or expose services securely.

Back to Blog Posts

1. Introduction

Networking is a core part of container orchestration. Docker provides flexible networking options to connect containers, expose services, and isolate workloads. Understanding these network modes is essential for building secure, scalable DevOps pipelines.

2. Default Networking Modes

Docker includes several built-in network drivers, each suited for different container communication needs.

๐ŸŸฆ Bridge (Default)

  • The standard network mode used for most containers

  • Containers share a virtual bridge interface

  • Communication supported via IP address or container name

  • Default behavior:

     
    docker run --network bridge

๐ŸŸฆ Host

  • Removes network isolation

  • Container uses the host’s network stack

  • High-performance, but less secure

     
    docker run --network host

๐ŸŸฆ None

  • Disables networking entirely

  • Useful for isolated workloads

     
    docker run --network none

๐ŸŸฆ Overlay (Swarm Mode)

  • Used for multi-host networking

  • Connects containers across multiple Docker hosts

  • Requires Docker Swarm

     
    docker network create -d overlay my-overlay

3. Creating Custom Networks

Custom networks enable clean service separation and name-based DNS communication.

 
docker network create my-net docker run --network my-net --name app1 nginx docker run --network my-net --name app2 alpine ping app1

4. Inspecting Networks

List all available networks:

 
docker network ls

Inspect network details:

 
docker network inspect bridge

5. Exposing Ports

Map container ports to host ports using -p:

 
docker run -p 8080:80 nginx

This exposes port 80 inside the container as 8080 on the host machine.

6. Best Practices

  • Use custom networks for controlled service isolation

  • Avoid host networking unless performance-critical

  • Use firewalls and reverse proxies for public-facing workloads

  • Monitor container traffic with tools like cAdvisor, Prometheus, or Weave Scope

7. Conclusion

Docker networking enables secure, flexible communication between containers and external systems. Understanding bridge, host, overlay, and custom networks helps you build scalable, production-ready DevOps environments.

Tomorrow’s post will cover Docker Volumes and Persistent Storage — don’t miss it!

Advertisement

A
ankit sharma

7 posts published

Sign in to subscribe to blog updates