port mapping
Port mapping publishes a service port through another network boundary.
Use this when A container runs but the browser cannot reach its service.
without the term
“The app runs in Docker and says it's listening on port 3000, but I can't open it in my browser. And my other container can't reach it on localhost either.”
with the term · How do you ask a model for port mapping?
Map this container service to the intended local host port. Verify access from the browser and a sibling container using their correct addresses.
What is port mapping?
A container listens on its own port, and Docker publishes that port on the host, for example 8080 on the host to 3000 in the container. 'localhost' inside a container means the container itself.
Why does port mapping matter when vibe coding?
Using localhost from the wrong network namespace can point back at the caller.
How do you do port mapping?
Trace the listener, published port, bind address, and each caller’s network context.
What goes wrong with port mapping?
Publishing the wrong internal port or unintentionally binding a private service publicly.