What Port 2705 Is
IANA's registry lists port 2705 as assigned to SDS Admin (sds-admin), registered for both TCP and UDP. That's where the trail goes cold. There's no RFC, no surviving documentation, and no apparent software using this name. The registration exists; the product apparently doesn't. 1
This happens more than you'd expect. The registered ports range (1024–49151) was claimed aggressively during the 1990s and early 2000s by companies and developers who registered names for products that were later abandoned, acquired, or simply forgotten. The IANA entry remains as a headstone.
The Range It Lives In
Port 2705 sits in the registered ports range (1024–49151), sometimes called user ports. These ports don't require elevated privileges to use on most operating systems, unlike well-known ports below 1024. Any application can open a socket here.
Registered ports are claimed through IANA's formal request process, but IANA doesn't police ongoing use — it just records the initial assignment. If the registrant disappears, the port sits reserved but idle in the registry. 2
Observed Unofficial Uses
LapLink Sharedirect — LapLink's PC-to-PC file transfer software has been documented as using ports in the 2700–2705 range, including port 2705, for its direct connection protocol. If you're setting up a router and need LapLink to work, this port may need to be forwarded. 3
KnowShowGo P2P — Some port databases note that the 2700–2800 range has been associated with the KnowShowGo peer-to-peer application, though port 2700 is the primary assignment. 4
Neither of these is the registered use. They're just what has actually been seen running here.
How to Check What's Using This Port
If port 2705 shows up in your network scans, it's almost certainly application-specific to whatever software opened it — not a well-known service.
On Linux/macOS:
On Windows:
The PID from netstat can be matched against Task Manager or tasklist to identify the owning process.
Why Unassigned Ports Matter
The registered ports range contains thousands of entries like this one — formally claimed, functionally empty. This matters for a few reasons:
- Firewall rules that block "all unassigned ports" need to account for the fact that IANA assignments and actual usage diverge constantly
- Security scanners may flag traffic on these ports as suspicious precisely because the expected service isn't well-known
- Port squatting — applications using an unregistered or ghost-registered port — is common and often harmless, but it means you can't rely on the port number alone to tell you what's running
When in doubt about an open port, check what process owns it. The registry is a hint, not a guarantee.
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