# What is Docker `expose` command?
The **`expose`** command is used to make a Docker container bind and listen on a specific port. It is up to the user to decide whether they want to listen on a *TCP* or a *UDP* connection -- the connection is TCP by default. The user can then specify the reliability protocol by adding either `/tcp` or `/udp` after the port number.

## Format
```terminal
# Exposes port 80 using TCP protocol

EXPOSE 80
# OR
EXPOSE 80/tcp

# Exposes port 80 using UDP protocol
EXPOSE 80/udp
```

# Expose vs. Publish
The user has three options when running a Docker container:
- Neither *expose* nor *publish*
- Only *expose*
- Both *expose* and *publish*

## Neither expose nor publish
The user restricts the communication with the container from *within the container only*. This approach is adopted by the user if the container at hand is running isolated from all the other containers.

## Only expose
The user restricts the communication with the container from *within the Docker*. It helps to establish inter-container communication in Docker.

## Both expose and publish
After *publishing*(`-p`) the container, the user allows communication with the container from **outside the Docker**.

> To publish a container, use the `-p` flag with the `run` command. 

Docker expose

Docker's expose command makes a container bind to a specific port, supporting TCP (default) and UDP. Users can expose, publish, or neither.

Docker expose

What is Docker expose command?

Format

Expose vs. Publish

Neither expose nor publish

Only expose

Both expose and publish

What is Docker `expose` command?