Port 2625: blwnkl-port — A registered name with no known story

What Range This Port Belongs To

Port 2625 falls in the registered port range (1024–49151), sometimes called User Ports.

The three port ranges serve different purposes:

Registered ports are available for any application or service to request assignment. IANA reviews the request, and if approved, the port gets a name and an entry. Unlike well-known ports (HTTP on 80, HTTPS on 443), registered ports carry no enforcement — nothing stops software from using an unrelated port, and nothing guarantees a registered name corresponds to active software.

The "blwnkl-port" Mystery

Some port lookup databases list port 2625 as blwnkl-port on both TCP and UDP. This name appears to have been drawn from an older IANA-adjacent registry, but there is no RFC documenting it, no company or product claiming it, and no explanation of what "blwnkl" means or refers to.

It is not an acronym. It is not a company name. It does not appear in technical literature. It may have been a placeholder, a typo that became permanent, or a private registration that never shipped anything. Whatever its origin, it effectively vanished without leaving a trail.

For practical purposes, treat port 2625 as unassigned.

Known Unofficial Uses

Older port intelligence databases list port 2625 as having been observed in traffic from several early-2000s applications, none of which designated it as a primary or exclusive port:

• Aces High — A WW2 multiplayer flight simulation game that used broad port ranges for peer-to-peer connections
• AIM Video IM — AOL Instant Messenger's video feature, which used dynamic ports across a wide range
• Audiogalaxy Satellite — A peer-to-peer music client from the early 2000s
• mIRC DCC — IRC's direct client-to-client file transfer, which negotiates ports dynamically

None of these applications specifically claimed or required port 2625. They used ranges that included it. These are old associations from a time when peer-to-peer software negotiated ports on the fly.

Today, if you see traffic on port 2625, it is almost certainly application-specific — a developer chose it for internal use, a game or service picked it arbitrarily, or something is misconfigured.

How to Check What Is Listening on This Port

On Linux or macOS:

# Show what process is bound to port 2625
ss -tlnp | grep 2625

# Or with lsof
lsof -i :2625

# Or with netstat
netstat -tlnp | grep 2625

On Windows:

# Show listening ports with process IDs
netstat -ano | findstr :2625

# Find the process by PID
tasklist | findstr <PID>

With nmap (from another machine):

nmap -p 2625 <target-ip>

Why Unassigned Ports Matter

The port number system works because services park at known addresses. HTTP at 80, SSH at 22 — these are stable rendezvous points. Your browser knows where to knock.

Unassigned ports are the gaps between those rendezvous points. They are not unused — software runs on them constantly. They just have no agreed-upon meaning. A firewall administrator looking at port 2625 traffic has no registry entry to consult. They have to find out the hard way: what process opened it, and why.

This is also why scanners watch unassigned ports closely. Malware and unauthorized services sometimes prefer obscure port numbers specifically because they lack official documentation. Unusual traffic on port 2625 warrants investigation, not because the port is inherently dangerous, but because there is no reference point for "normal."