What This Port Is
Port 2704 sits in the registered port range (1024–49151), the middle tier of the port number system. Registered ports have gone through IANA's assignment process — someone asked, IANA approved, and the entry persists in the registry.
This port is registered to sms-remctrl, part of a four-port suite Microsoft used for Systems Management Server (SMS) remote control tools. Despite the name, "SMS" here has nothing to do with text messaging. It stands for Systems Management Server, Microsoft's enterprise IT management platform from the late 1990s and early 2000s.
The Four-Port Suite (2701–2704)
Microsoft registered four consecutive ports for SMS remote tools:1
| Port | Function |
|---|---|
| 2701 | Contact, reboot, ping (RC Info) |
| 2702 | Remote desktop control |
| 2703 | Chat between administrator and user |
| 2704 | File transfer |
Each function got its own port. An IT administrator running the SMS Remote Tools console would connect to a client machine across all four simultaneously — watching the screen on 2702 while chatting on 2703 and pushing files on 2704.
Why It's Dormant
SMS 2003 reached end-of-life in April 2011.2 Its successor, Microsoft System Center Configuration Manager (SCCM), uses entirely different ports and protocols. No modern software is registered against port 2704, and seeing traffic on it would be unusual.
The IANA registration persists — that's how registrations work. Once assigned, they stay in the registry indefinitely unless explicitly revoked. Port 2704 will likely remain listed as sms-remctrl long after everyone who ever ran SMS 2003 has retired.
Checking What's on This Port
If you see activity on port 2704 on your system and want to know what's there:
On Linux/macOS:
On Windows:
The output includes a process ID (PID). Cross-reference it in Task Manager or with tasklist on Windows, ps aux on Linux.
On a modern system, nothing should be listening on 2704. If something is, it warrants investigation.
Why Unassigned and Dormant Ports Matter
The registered port range contains thousands of entries like this one — registrations from software that peaked in the early 2000s and quietly exited. They matter for a few reasons:
Firewall rules outlive software. A rule allowing port 2704 traffic, written in 2003, might still exist on a network today. Dead registrations create ghost permissions.
Port scanners see them. Security tools that flag unusual open ports use the IANA registry to determine what's expected. An open 2704 looks suspicious because nothing legitimate should be there anymore.
They're not available for reuse without IANA action. Until IANA revokes a registration, that port isn't cleanly available for new software. The registered range has thousands of these squatted entries.
The port system was designed to be orderly. The reality is messier: a graveyard of registrations from software that came, shipped, and disappeared, each one holding its number forever.
Byla tato stránka užitečná?