01 · Documentation

Find out exactly which process or Windows service owns a TCP or UDP port. Everything here describes the current implementation; planned behaviour is labelled as planned.

Sheet index · 7 pages

Sheet	Section	Page
A-01	Getting started	Quick start What PortWho answers, how the command line is built from source today, the first three commands to try, and how to read the table, the details view and the exit codes.
B-02	Core concepts	How PortWho resolves port owners The Windows APIs behind each column, from the IP Helper endpoint tables and PID to process mapping to service mapping through the service control manager and offline Authenticode verification with embedded and catalog signatures.
C-03	CLI	Command-line reference Every argument and option of the portwho command line, with exact spellings and aliases, the --option=value form, mutually exclusive combinations and their error messages, output modes, exit codes and examples.
C-04	CLI	JSON output The schema version 1 contract of portwho --json, the full document shape, every field with its type and meaning, the exact enumerations, the stability promise and a PowerShell example that filters the result.
D-05	Troubleshooting	Troubleshooting What to do when a port is in use but PortWho lists nothing, what (access denied), (exited), unavailable and INVALID mean, how to speed up slow runs, and the known limitations of the current command line.
E-06	FAQ	FAQ Short answers about PortWho's price, safety, privileges, network use, process termination, the desktop application, download verification, support and supported Windows versions.
F-07	Security and privacy	Security and privacy PortWho's read-only guarantees, its lack of network use, telemetry and accounts, exactly what it reads from the system, how it keeps to least privilege, the signing plan for releases, data retention and how to report a vulnerability.