The first useful check
A published container port changes the host’s reachable surface, and the default bind address matters.
Inputs and prerequisites
Inspect the compose or Docker run configuration, the host address, and whether the service is meant to be public, loopback-only or reachable through a reverse proxy.
A small, reversible procedure
Use an explicit bind address for the intended exposure, then verify from a separate machine where practical. Review Docker’s firewall behavior before assuming a host firewall rule covers a published port.
What to record after the check
Keep the port mapping, intended clients, proxy configuration and an external observation in the operating record.
Scope and service boundary
This article does not configure a firewall for you or promise that a given network path is blocked. Malaysia, Romania and Switzerland are server-country choices; they do not establish a backup country, facility detail, stock or measured network result.
Documentation used
Primary references for this page. Check the documentation for the version installed in your own environment.