The TIP listener of Microsoft's Distributed Transaction Coordinator — a Windows transaction plane, not an application port.
IANA registers 3372 as tip2 (Transaction Internet Protocol), and Microsoft's MSDTC service listens there for its TIP transaction-manager facet, which lets a Windows transaction coordinator interoperate with non-Microsoft transaction managers. You will see it on SQL Server boxes, BizTalk hosts, and COM+ application servers where distributed transactions are enabled; MSDTC's main OleTx traffic still goes through the RPC endpoint mapper on 135 plus a dynamic port. A configuration flag controls whether the TIP facet will accept a connection from a source port other than 3372.
Do not expose
This is a transaction-control plane between trusted servers, historically a DoS target, and it pairs with RPC on 135 — keep it on an internal segment behind a firewall rule that names the specific peer hosts.
$ nc -vz -w 3 TARGET 3372Seen 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.