What This Port Is
Port 3682 sits in the registered port range (1024–49151) — the middle tier of the port numbering system, where IANA records formal service claims made by companies and organizations. Unlike the well-known ports below 1024, registered ports don't come with tight control or enforcement. They're a reservation system on the honor code.
According to the IANA registry, port 3682 is assigned to cas-mapi, described as "EMC SmartPackets-MAPI." It was registered in January 2003 under an assignee named Koen Schoofs. 1
What EMC SmartPackets-MAPI Was
EMC (now part of Dell Technologies) was a major enterprise storage and infrastructure company in the early 2000s. MAPI — the Messaging Application Programming Interface — is Microsoft's protocol for communication between email clients like Outlook and servers like Exchange. It's a notoriously chatty protocol: it generates a lot of round-trips, which made it painful over slow WAN links.
"SmartPackets" appears to have been an EMC technology for optimizing that traffic — compressing or caching MAPI conversations to make Exchange usable across wide-area networks. WAN optimization for MAPI was a real category in enterprise networking around 2003, addressed by products from multiple vendors.
The product left no footprint. No documentation, no press releases, no support forums. It was either absorbed into other EMC product lines, discontinued, or never widely shipped. The port registration is the only evidence it existed.
What You'll Actually Find Here
If you scan port 3682 on a modern network, you're not going to find SmartPackets. That product is gone. What you might find:
- Nothing — the most common result
- Custom application traffic — developers sometimes pick obscure registered ports because they appear "available"
- Malware — attackers occasionally use low-profile registered ports to blend in with legitimate-looking traffic
How to Check What's Listening
On Linux or macOS:
On Windows:
If something is listening on 3682 and you don't recognize it, that's worth investigating. The SmartPackets service is not the explanation.
Why These Registrations Exist
IANA doesn't require companies to surrender port registrations when products are discontinued. The registry is append-friendly and reclaim-averse. So it accumulates: ports claimed in 1998, 2003, 2011 for products that shipped to a handful of enterprise customers and then quietly died. They remain registered, their entries unchanged, long after anyone could tell you what the software actually did.
Port 3682 is one of hundreds of these. Technically assigned. Practically empty. A street address for a building that was demolished.
האם דף זה היה מועיל?