What This Port Is
Port 3660 belongs to the registered port range (1024–49151). These ports are formally assigned by IANA (the Internet Assigned Numbers Authority) to specific services and applications. Unlike the well-known ports below 1024, you don't need elevated privileges to bind to them — but they're still tracked and claimed.
Port 3660 has an IANA registration: can-nds-ssl, short for Candle Directory Services using SSL. 1
The Candle Corporation Story
Candle Corporation was a Californian enterprise software company that built monitoring and management tools for mainframes and distributed systems. In the early 2000s, IBM acquired Candle and folded its products into the IBM Tivoli line — an umbrella brand for IBM's IT management software.
Port 3660 was registered for Candle's directory service using SSL-encrypted communication. IBM Tivoli inherited the registration when it inherited the product. 2
Tivoli Monitoring agents cluster around this neighborhood: port 3660 for the SSL directory service, with port 3661 used by related agents. Neither port appears in most network audits today because the Tivoli product line, while still supported, runs in specialized enterprise environments — mainframe shops, large financial institutions, data centers that have been running the same stack for twenty years.
Star Wars: Empire at War
Star Wars: Empire at War, Petroglyph's 2006 real-time strategy game, uses ports 3658–3660 (TCP and UDP) for its online multiplayer functionality, alongside a range of GameSpy infrastructure ports. 3
This is a classic registered-port collision. Petroglyph's multiplayer client picked a block of ports in the 36xx range. Port 3660 was technically spoken for — but "spoken for by legacy IBM enterprise software" is effectively the same as unoccupied for a home user trying to play a PC strategy game. The odds of conflict are negligible.
The Empire at War servers are long offline. But players running LAN matches or using fan-maintained servers still route traffic through these ports.
What It Means in Practice
For almost everyone, port 3660 is functionally unassigned. Unless you're running IBM Tivoli monitoring infrastructure (in which case you already know exactly what's on this port), you won't encounter can-nds-ssl traffic. The IANA registration exists, the original occupant rarely appears, and other software has quietly moved in.
This is how the registered port space works in the middle of the range: official ownership, practical vacancy, opportunistic reuse.
How to Check What's Listening
If you see activity on port 3660 and want to know the source:
macOS / Linux:
Windows:
Cross-reference the process ID with Task Manager or ps aux to identify the application. If nothing appears, nothing is listening — the port is closed.
Related Ports
- 3658–3659 — Also used by Star Wars: Empire at War multiplayer
- 3661 — IBM Tivoli Monitoring agent port (neighbor to can-nds-ssl)
- 636 — Standard LDAPS port (SSL-encrypted LDAP directory service, the well-known equivalent of what 3660 handles in Tivoli)
Frequently Asked Questions
Ήταν χρήσιμη αυτή η σελίδα;