How can two containers communicate with each other by name?

Answer 1

Two containers can communicate with each other by name when they are connected to the same Docker network (especially a user-defined bridge network).

Here’s how it works conceptually (no commands, no code 🙂):

Docker has a built-in DNS service

When containers are on the same user-defined network, Docker automatically:

Registers each container’s name as a hostname

Resolves that name to the container’s IP address

This means one container can reach another using just the container name instead of an IP address

Important notes:

This works on user-defined networks, not the default bridge network

Container names act like hostnames

No manual IP management is needed (IPs can change, names don’t)

Example in plain words:

If two containers are on the same network and one is named database, the other container can talk to it using the name database.