{
  "port": 2811,
  "protocol": "tcp",
  "service": "GridFTP (GSI FTP)",
  "oneLiner": "A GridFTP server's control channel — bulk research data transfer with X.509 authentication.",
  "whatItIs": "GridFTP extends FTP with GSI (X.509 proxy certificate) authentication, parallel streams, and third-party transfers, and its server listens on TCP 2811 for the control channel while data moves over a separately configured high port range. It came from the Globus Toolkit, now maintained as the Grid Community Toolkit, and it is the transfer backend behind Globus endpoints at national labs, HPC centres, and university research storage. Commands look like FTP; the credential exchange does not.",
  "exposure": {
    "verdict": "careful",
    "note": "Internet-facing is the normal deployment — the transfers are cross-site by design and authenticated with certificates — but the data-channel port range must be opened deliberately and the server kept patched."
  },
  "checkCommand": "nc -w 3 TARGET 2811 | head -1",
  "links": [
    {
      "title": "Grid Community Toolkit — GridFTP System Administrator's Guide (control channel on 2811)",
      "url": "https://gridcf.org/gct-docs/latest/gridftp/admin/index.html",
      "kind": "official-docs"
    },
    {
      "title": "gridcf/gct — Grid Community Toolkit source",
      "url": "https://github.com/gridcf/gct",
      "kind": "github"
    },
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry — 2811 (gsiftp)",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=2811",
      "kind": "iana"
    }
  ],
  "ianaName": "gsiftp"
}