WHOSEPORT
Investigations · guide

Two servers on one port

Requests reach a server you did not expect, with no error anywhere. Two processes can hold the same port, one on IPv4 and one on IPv6.

Ask

bash
whoseport 4000

What WhosePort checks

  • Every listener on the port, with its PID and IPv4 or IPv6
  • Which project and command each process belongs to

Typical root cause

Another project's server is still running on the same port. "localhost" resolves to either address, so clients reach whichever answers first.

Proposed fix

  • stop_process on the server you do not need (approval required)
  • Or move one of the two to another port
Approval
Every step that changes your machine is a typed action classed by the policy engine. It waits for your approval in the dashboard, which shows the target, risk and expected effect first. A changed .env file is backed up before it is written. See /docs/policy.

Verification

  • Only one process owns the port
  • The expected server answers