Docker Network Types Differentiated

February 19, 2025

The source of this post is my own notes taken while watching a NetworkChuck youtube video and then expanded by ChatGPT.

Docker Network Types

1. Default Bridge Network

The default bridge network is created automatically when Docker is installed. It uses the docker0 virtual bridge interface, which acts as a switch connecting containers.

Key Features:

Containers connected to the bridge can communicate with each other.
The default bridge provides DHCP, assigning IPs to containers.
The host cannot access containers unless ports are explicitly exposed.
Uses the host’s DNS settings (/etc/resolv.conf).

Commands:

List Docker networks:
```
sudo docker network ls
```
Inspect the default bridge network:
```
sudo docker inspect bridge
```

Expose a container port to the host:

sudo docker run -itd --rm -p 80:80 --name web nginx

2. User-Defined Bridge Network

A user-defined bridge network is a custom bridge network that provides better isolation and container name resolution.

Key Features:

Custom network isolation (does not interact with the default bridge).
Automatic DNS resolution between containers on the same network.
Recommended over using the default bridge.

Commands:

Create a user-defined bridge network:
```
sudo docker network create asgard
```

Start a container in the custom network:

sudo docker run -itd --rm --network asgard --name loki busybox

Inspect the network:
```
sudo docker inspect asgard
```

3. Host Network

A container using the host network shares the host’s network stack, meaning:

No subnet, no virtual interfaces – it directly uses the host’s network.
No port forwarding required.
Best for performance-sensitive applications like VPNs (e.g., WireGuard).

Commands:

Run a container in the host network:

sudo docker run -itd --rm --network host --name nginx01 nginx

4. MACVLAN Network

MACVLAN allows containers to appear as physical devices on the network, each with its own MAC address and IP.

Key Features:

Containers behave as if they are separate physical devices on the network.
Requires enabling promiscuous mode on the host interface.
DHCP is not available; static IP assignment is required.

Commands:

Create a MACVLAN network:

sudo docker network create -d macvlan     --subnet 192.168.33.0/24     --gateway 192.168.33.1     -o parent=en1     macvlan-plab

Start a container in the MACVLAN network:

sudo docker run -itd --rm --network macvlan-plab --ip 192.168.33.25 --name busybox01 busybox

5. IPVLAN Network

IPVLAN is similar to MACVLAN but allows containers to share the host’s MAC address while getting unique IPs.

Modes:

L2 Mode: Containers share the same subnet as the host.
L3 Mode: Containers use routed networking (requires static routes).

Commands:

Create an L2 IPVLAN network:

sudo docker network create -d ipvlan     --subnet 192.168.7.0/24     --gateway 192.168.7.1     -o parent=enp0s3 netname

Create an L3 IPVLAN network:

sudo docker network create -d ipvlan     --subnet 192.168.94.0/24     -o parent=enp0s3 -o ipvlan_mode=l3     --subnet 192.168.95.0/24 newl3network

6. Overlay Network

Used in Docker Swarm, the overlay network allows containers across multiple hosts to communicate.

Key Features:

Abstracts inter-host communication complexity.
Uses VXLAN tunneling to connect containers across hosts.

Commands:

Create an overlay network:

sudo docker network create -d overlay my_overlay

7. None Network

A container with --network none has no network access.

Commands:

Run a container with no network:

sudo docker run -itd --rm --network none --name isolated busybox

Docker