The Btrieve MicroKernel database engine port, still carrying Actian Zen and Pervasive PSQL traffic.
IANA registers 3351 as btrieve, and it remains the listening port of the MicroKernel Engine in Pervasive PSQL and its successor Actian Zen — the modern descendants of Btrieve. Clients reach databases through it directly, including URIs of the form btrv://servername:port/database, and Actian's documentation recommends not changing the assignment. It turns up wherever vertical-market Windows applications ship an embedded Zen database: point-of-sale, dental and veterinary practice software, small ERP systems. An open 3351 means a business application's data files are reachable over the network.
Do not expose
It is a database engine port with the application's records behind it and no transport encryption by default; keep it on the LAN and reach it over a VPN.
$ nc -vz TARGET 3351Seen 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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