TCP 8021
Synopsis
- TCP port 8021 is registered for ftp-proxy and is commonly used by firewall FTP proxy helpers.
- OpenBSD’s ftp-proxy (with pf) typically listens on 127.0.0.1:8021, with pf rules redirecting external FTP control traffic (port 21) to it for protocol fixing and tracking.
- pfSense and OPNsense use the same ftp-proxy service/plugin, which by default binds to 127.0.0.1:8021 to manage active/passive FTP through their firewalls.
- Zope 2’s ZServer includes an FTP service that by default listens on TCP 8021, used in real deployments (e.g., Plone/Zope) for managing content via FTP.
- Security note: Misconfigured or exposed ftp-proxy on 8021 can be abused as an open proxy or to bypass firewall controls, so it is sometimes targeted in scans.
Observed activity
Last 30 days
Detailed chart