Hey @yunwool
I would recommend writing export ROS_DOMAIN_ID=1 in your ~/.bashrc and then restarting all terminals so the change takes effect. This should prevent other ROS 2 messages from appearing in your environment, since you’ll effectively be using your own domain.
Optionally, you may want to look into the ROS_LOCALHOST_ONLY variable as well, since I do believe if someone else sets their domain ID to 1, you would see their messages.