Port 2955: CSNOTIFY — A Registered Name with No Public Story

What This Port Is

Port 2955 sits in the registered port range (1024–49151), the middle tier of the port numbering system. IANA maintains this range for services that have requested an official assignment — software vendors, protocol authors, and developers who want a stable, recognized home for their traffic.

The registered name is csnotify. The assignee on record is Israel Beniaminy. Both TCP and UDP are listed. Beyond those facts, the public record goes silent.

No RFC was published. No open-source implementation uses this port by name. No documentation explains what "CS Notify" notifies, what system it serves, or whether it was ever deployed. It's a registration without a public story — which happens more often than you'd expect.

What the Registered Port Range Means

When someone requests a port registration from IANA, they're asking for a reserved label in a global namespace. The process doesn't require that the software be open-source, widely deployed, or even publicly available. Private applications, internal enterprise tools, and products that never shipped all have entries in the registered port range.

This is by design. The alternative — only registering ports for widely-used public protocols — would create conflicts as private software spread across networks. A registered port, even for an obscure service, reduces the chance that two unrelated applications end up fighting over the same number.

Port 2955 is one of hundreds of registered ports where the registration exists but the software behind it never became part of the public record.¹

Any Observed Unofficial Uses

Some security databases flag port 2955 as historically associated with scanning or suspicious traffic — a common note for any port that doesn't have active, known-good traffic to distinguish itself from background noise. There's no documented malware family specifically targeting or using this port.²

If you see traffic on port 2955 in your environment, it's almost certainly an application-specific choice made by whatever software is running there, not a reference to the IANA registration.

How to Check What's Listening

If port 2955 is active on a system you administer, standard tools will tell you what process owns it:

Linux/macOS:

# Show the process listening on port 2955
ss -tlnp | grep 2955

# Or with lsof
lsof -i :2955

Windows:

# Show listening port with owning process ID
netstat -ano | findstr :2955

# Resolve the PID to a process name
tasklist | findstr <PID>

The process name will tell you more than any port database can.

Why Gaps in the Registry Matter

The registered port range has over 48,000 possible entries. Many are blank. Many hold registrations like this one — technically assigned, practically invisible. This is the port numbering system doing its job: reserving space, preventing collisions, maintaining a record even when the software behind that record doesn't make headlines.

Port 2955 is a reminder that the registry is a coordination mechanism, not a catalog of what's actually running. The interesting things happening on your network are better found with ss and lsof than with any port list.