# Docker Networks

## Purpose

Docker networks allow containers to communicate with each other while remaining isolated from other containers and the host system.

## Networks in Use

| Network                  | Purpose                  |
| ------------------------ | ------------------------ |
| bridge                   | Default Docker network   |
| compose-practice_default | Docker Compose nginx lab |
| gitea_default            | Gitea service            |
| npm_default              | Nginx Proxy Manager      |
| portainer_default        | Portainer                |
| uptime-kuma_default      | Uptime Kuma              |

## Observations

Each Docker Compose stack automatically creates its own network.

Examples:

| Service                  | Container IP |
| ------------------------ | ------------ |
| uptime-kuma              | 172.17.0.2   |
| compose-practice-nginx-1 | 172.18.0.2   |
| gitea                    | 172.19.0.2   |
| npm                      | 172.20.0.2   |
| portainer                | 172.21.0.2   |

## Commands

View networks:

```bash
docker network ls
```

Inspect a network:

```bash
docker network inspect NETWORK_NAME
```

Example:

```bash
docker network inspect gitea_default
```

## Lessons Learned

* Every Compose stack gets its own network.
* Containers communicate using private Docker IP addresses.
* Containers on separate networks cannot automatically communicate with each other.
* Docker networks provide isolation and security.
* Reverse proxies often require containers to share a network.

## Date Created

June 15, 2026