What This Port Is
Port 2741 sits in the registered ports range (1024–49151), the middle tier of the port numbering system. IANA officially lists it as assigned to a service called TSB — short for Terminal Services Broker — on both TCP and UDP.1
That's the entire official record. No RFC. No protocol specification. No assignee contact. No description beyond the abbreviation.
This is more common than you'd expect. The registered range was populated over decades, and many early assignments were logged with nothing more than a name. Some of those services were real and simply never documented publicly. Others were reserved speculatively and never built. Either way, the registry entry is now a placeholder — a name that tells you someone once cared about this port, but not why.
Who Actually Uses It
Veeam ONE uses port 2741 internally as the communication channel between Veeam ONE Web Services and the Veeam ONE Server's internal Web API.2 It's a backend-to-backend channel — not something users connect to directly. The public-facing port for Veeam ONE is 1239. Port 2741 is the behind-the-scenes plumbing.
If you see port 2741 open on a machine running Veeam ONE, that's expected. If you see it on a machine that has no Veeam software, something else claimed the space.
How to Check What's Listening
On Linux/macOS:
On Windows:
The process ID from netstat maps to a running service in Task Manager or via:
Why Unassigned (and Ghost-Assigned) Ports Matter
The registered port range exists so software vendors can claim a consistent home without colliding with each other. Port 80 will always be HTTP. Port 443 will always be HTTPS. That predictability matters for firewalls, monitoring tools, and network operators who need to write rules that hold.
When a port carries a name but no documentation — like port 2741 — it creates ambiguity. Administrators can't easily distinguish between the ghost-assigned "TSB" service, Veeam's internal API, and something unexpected. Security tools flag it as unknown. Firewall rules become guesswork.
This is why port documentation matters. An undocumented open port isn't necessarily malicious, but it's a question that has to be answered manually every time someone encounters it.
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