Ah! That is not an issue of testcontainers. In our Jenkins every pipeline it dockerized and uses agents. So it is not running on the host directly. However it is also not running dind (Docker in Docker). Instead it is important to use dood (docker out of docker), which is best practice anyway. Your CI needs to be configured once and all your problems should go away IF tests have randomised ports or even better also run in docker so that those ports do not need to be exposed on host level. Most of my colleagues however prefer not to use dev containers so randomised ports was the solution for us for now.