Docker network without Docker

Docker networking isn't magic. See how to build its core features from scratch using only fundamental Linux utilities like bridges, veth pairs, and iptables.

#1about 2 minutes

Understanding container isolation with namespaces and cgroups

Containers use Linux namespaces for process isolation and cgroups for resource limiting, which necessitates explicit networking configurations for communication.

#2about 5 minutes

Establishing host-to-container communication with virtual ethernet pairs

A virtual ethernet (veth) pair acts as a point-to-point virtual cable, connecting a container's isolated network namespace directly to the host system.

#3about 5 minutes

Using virtual bridges for multi-container communication

A virtual network bridge functions like a physical switch, allowing multiple containers to communicate with each other through a single shared interface.

#4about 11 minutes

Analyzing Docker's IPtables rules for network isolation

Docker automatically creates IPtables rules in chains like DOCKER-ISOLATION-STAGE-1 to prevent unwanted traffic between different custom networks by default.

#5about 5 minutes

Manually configuring port forwarding for a running container

Port forwarding is achieved by adding a Destination NAT (DNAT) rule to the IPtables nat table, which can be added or modified for an already running container.