Internet-Security.com TCP port 8989 details

Sonarr (formerly NZBDrone) uses TCP port 8989 by default for its web interface and API on Windows, Linux, macOS, and common Docker images (e.g., linuxserver/sonarr).
This same 8989/TCP mapping is used by Sonarr packages on platforms like Unraid, Synology (community packages), and TrueNAS SCALE charts.
Security note: Port 8989 is frequently scanned on the internet because many Sonarr instances are exposed; attackers have abused misconfigurations and past Sonarr vulnerabilities to gain unauthorized access or execute code, so it should be secured or kept behind a reverse proxy.

TCP 8989