Port 2845: BPCP Trap — A Protocol That Outlived Its Creator

Port 2845 is registered. It has a name — bpcp-trap — and a companion on port 2844 (bpcp-poll). What it doesn't have is much of a living presence on the Internet.

What BPCP Is

BPCP stands for Best Power Control Protocol (or a close variant). The clue is in the registrant: Steve Van Duser, whose IANA contact email was at bestpower.gensig.com — a domain belonging to Best Power Technology, a UPS (Uninterruptible Power Supply) manufacturer that was eventually absorbed into larger corporate structures during the consolidation of the power management industry in the late 1990s and early 2000s.¹

The naming pattern makes the intent clear:

• Port 2844 — bpcp-poll: The active side. Your management software asks the UPS, "How are you doing?"
• Port 2845 — bpcp-trap: The passive side. The UPS speaks up on its own: "Something happened. Pay attention."

This is the same polling/trap architecture that SNMP made standard, but predating or running alongside it as a proprietary alternative. At the time, UPS vendors often built their own management protocols before industry-wide standards solidified.²

What the Range Means

Port 2845 sits in the registered port range (1024–49151). Registered ports are officially assigned by IANA to specific services and organizations — they're not arbitrary. But registration doesn't equal activity. The IANA registry is littered with ports assigned to protocols that shipped with one product line, were never adopted broadly, and now exist only as entries in a database.³

That's port 2845. Registered. Legitimate. Quiet.

Is Anything Actually Using It?

Almost certainly not BPCP. If you see traffic on port 2845 today, it's more likely:

• A custom application that picked the port arbitrarily (rare but it happens)
• A misconfigured service
• A scanner probing registered ports

The protocol itself has no public documentation, no open-source implementations, and no observed traffic in modern security datasets.

How to Check What's Listening on Port 2845

If you're seeing traffic on this port or want to verify nothing unexpected is running on your system:

Linux/macOS:

# Show what process is listening on port 2845
ss -tlnp | grep 2845

# Or with lsof
lsof -i :2845

Windows:

netstat -ano | findstr :2845

From another machine (check if port is open):

nc -zv <host> 2845
# Or
nmap -p 2845 <host>

If nothing is listening, that's expected. Port 2845 has been empty for a long time.

Why This Matters

Unassigned and dormant ports like 2845 matter for a simple reason: the IANA registry is not the Internet. Traffic on a registered port doesn't mean that service is running, and absence from the registry doesn't mean a port is safe to use freely.

When you see an unknown port in your firewall logs, the registered name is a starting point — not an answer. BPCP Trap tells you the port's origin story. It doesn't tell you what's actually there today.