I’m having trouble configuring Docker networking on my Ubuntu 24.04 host, and I could really use some help.

Environment:

• Host OS: Ubuntu 24.04
• Host IP: 10.78.20.20 (running on an ESXi machine)
• Docker is installed and running fine.
• I am new to Docker.

I can successfully run a Docker container and access it through the host IP (10.78.20.20). However, I want to assign a different IP to this container, such as 10.78.20.40.

Here is a snippet from my docker-compose.yml where I attempted to set up a custom bridge network:

networks:
  custom_bridge:
    driver: bridge
    ipam:
      config:
        - subnet: 10.78.20.0/24
          gateway: 10.78.20.1

services:
  my_service:
    image: my_image
    networks:
      custom_bridge:
        ipv4_address: 10.78.20.40

Unfortunately, this configuration didn’t work as expected. The container is still not accessible via the new IP address.

I tried several other guides and tutorials from the internet, but none of them solved my issue.

Question:
How can I properly configure Docker to assign a specific IP address (10.78.20.40) to my container on my current setup?

Any help or guidance would be greatly appreciated!