{
  "port": 648,
  "protocol": "tcp",
  "service": "RRP (Registry Registrar Protocol)",
  "oneLiner": "The old domain-registrar protocol for .com/.net registries, retired in favour of EPP.",
  "whatItIs": "RRP is documented in RFC 2832 as the NSI Registry Registrar Protocol version 1.1.0 — an Informational, not standards-track, specification for a 7-bit US-ASCII text protocol on TCP 648 that let accredited registrars add, delete, and modify second-level domain registrations in a TLD registry. It was Network Solutions' interface for the shared registry system. The industry replaced it with EPP (RFC 5730, STD 69), which registries run on TCP 700, so there is no live RRP service to find today.",
  "exposure": {
    "verdict": "never",
    "note": "A retired registry provisioning interface — it carried the authority to change domain registrations, and nothing should be answering on it now."
  },
  "checkCommand": "nc -vz -w 3 TARGET 648",
  "links": [
    {
      "title": "RFC 2832 — NSI Registry Registrar Protocol (RRP) Version 1.1.0",
      "url": "https://www.rfc-editor.org/rfc/rfc2832.html",
      "kind": "spec"
    },
    {
      "title": "RFC 5730 — Extensible Provisioning Protocol (EPP), the replacement",
      "url": "https://www.rfc-editor.org/rfc/rfc5730.html",
      "kind": "spec"
    },
    {
      "title": "IANA Service Name and Transport Protocol Port Number Registry — 648",
      "url": "https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=648",
      "kind": "iana"
    }
  ]
}