Docker Expose Port 443

Expose Port 443 in Docker

docker run -p 443:443 your-image-name
		

This command maps container port 443 to the same port on the host machine.

Dockerfile Example

FROM node:18-alpine
WORKDIR /app
COPY . .
EXPOSE 443
CMD ["npm", "start"]
		

The EXPOSE instruction documents that the container listens on port 443.

EXPOSE vs Publish (-p)

• EXPOSE 443 documents the port inside the container.
• -p 443:443 makes the port accessible from the host.
• Exposed ports are not reachable unless published.

Docker Expose Port 443 Not Working

If Docker expose port 443 is not working, it is usually due to incorrect port publishing, an application not listening on the expected port, or a port conflict on the host machine.

Port 443 Already in Use

The error “port 443 already in use” means another process is already bound to that port on your host system.

# Find process using port 443
lsof -i :443

# OR use a different host port
docker run -p 8080:443 your-image-name
		

• Ensure your app is listening on port 443 inside the container
• Verify the port is published using -p
• Check firewall or network rules
• Avoid conflicts with existing services

Related Docker Expose Port Guides