docker-networking

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Configure Docker networking for containers including bridge, overlay, and service discovery

⭐1stars🔀0forks📁View on GitHub🕐Updated Dec 31, 2025
[Cloud Infrastructure]

When & Why to Use This Skill

This Claude skill provides comprehensive tools and guidance for mastering Docker networking. It enables users to configure various network drivers like bridge, overlay, and macvlan, manage service discovery, and implement secure network isolation. Designed for both development and production, it streamlines container communication and simplifies complex troubleshooting tasks to ensure robust cloud-native infrastructure.

Use Cases

  • Isolating multi-tier applications: Create custom bridge networks to separate frontend, backend, and database services, ensuring that internal databases are not exposed to the public internet.
  • Multi-host communication: Configure encrypted overlay networks to enable secure and seamless communication between containers running across different physical hosts in a Docker Swarm cluster.
  • Service Discovery: Implement reliable service-to-service communication using container names as hostnames, eliminating the need for hardcoded IP addresses in microservices.
  • Network Troubleshooting: Quickly diagnose and resolve connectivity issues, DNS failures, and port conflicts using standardized diagnostic commands and step-by-step checklists.
  • High-Performance Networking: Deploy containers with host or macvlan drivers for specialized applications that require direct access to the host's network stack or physical network interfaces.
namedocker-networking
descriptionConfigure Docker networking for containers including bridge, overlay, and service discovery
sasmp_version"1.3.0"
bonded_agent03-docker-networking
bond_typePRIMARY_BOND

Docker Networking Skill

Master Docker networking concepts and configuration for container communication, service discovery, and network isolation.

Purpose

Configure and troubleshoot Docker networks for development and production environments with proper isolation and service discovery.

Parameters

Parameter Type Required Default Description
driver enum No bridge bridge/overlay/host/macvlan
subnet string No - Custom subnet CIDR
internal boolean No false Internal-only network

Network Drivers

Driver Use Case Multi-Host Encryption
bridge Single host, default No No
overlay Swarm, multi-host Yes Optional
host Max performance No N/A
macvlan Physical network No No
none Disable networking No N/A

Configuration Examples

Custom Bridge Network

# Create network with custom subnet
docker network create \
  --driver bridge \
  --subnet 172.28.0.0/16 \
  --gateway 172.28.0.1 \
  my_network

# Run container on network
docker run -d --name app \
  --network my_network \
  nginx:alpine

Docker Compose Networking

services:
  frontend:
    image: nginx:alpine
    networks:
      - public
    ports:
      - "80:80"

  backend:
    image: node:20-alpine
    networks:
      - public
      - private
    expose:
      - "3000"

  database:
    image: postgres:16-alpine
    networks:
      - private  # Internal only

networks:
  public:
    driver: bridge
  private:
    driver: bridge
    internal: true  # No external access

Service Discovery

# Containers can reach each other by service name
services:
  app:
    image: myapp
    environment:
      # Use service name as hostname
      DATABASE_HOST: database
      CACHE_HOST: redis

  database:
    image: postgres:16-alpine

  redis:
    image: redis:alpine

Overlay Network (Swarm)

# Create encrypted overlay
docker network create \
  --driver overlay \
  --attachable \
  --opt encrypted \
  my_overlay

Port Mapping

# Map host:container
docker run -p 8080:80 nginx

# Bind to specific interface
docker run -p 127.0.0.1:8080:80 nginx

# Random host port
docker run -P nginx

# UDP port
docker run -p 53:53/udp dnsserver

Error Handling

Common Errors

Error Cause Solution
network not found Typo or deleted Create network
address in use Port conflict Change port
cannot reach Wrong network Check network membership
DNS failed Service not ready Add health checks

Fallback Strategy

  1. Verify network exists: docker network ls
  2. Check container membership: docker network inspect <net>
  3. Test DNS: docker exec app nslookup backend

Troubleshooting

Debug Checklist

  • Network created? docker network ls
  • Container connected? docker inspect <container>
  • DNS resolving? nslookup from container
  • Port mapped? docker port <container>

Diagnostic Commands

# List networks
docker network ls

# Inspect network
docker network inspect my_network

# Test connectivity
docker exec app ping -c 3 database

# Check DNS
docker exec app nslookup backend

# View port mappings
docker port container_name

Network Debugging

# Enter container network namespace
docker exec -it app sh

# Check DNS resolution
cat /etc/resolv.conf
nslookup database

# Check connectivity
ping -c 3 backend
curl http://backend:3000/health

Usage

Skill("docker-networking")
  • docker-compose-setup
  • docker-swarm