NRPC — the protocol Notes clients and Domino servers use for mail, databases, directory and replication.
Notes Remote Procedure Call (NRPC) is the foundation of communication between Notes workstations and Domino servers and between Domino servers themselves, and by default every NRPC connection uses TCP 1352. It carries database access, directory lookups, mail routing and server-to-server replication in one proprietary protocol. Because IANA assigned the port to Domino, little else competes for it, so 1352 open is a reliable indicator of a Domino server. Domino's Internet services (HTTP, SMTP, IMAP) run on their own ports, not this one.
Expose with care
Internet-facing 1352 is normal for cross-organisation Domino replication, but it is an authenticated application port on a large legacy codebase — restrict it to known partner networks and enable port encryption rather than leaving it open to the world.
$ nmap -Pn -p 1352 -sV TARGETSeen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
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Corrections or a missing port? Reply @rimrocksystems.