What Port 2366 Is
Port 2366 is registered with IANA under the service name qip-login — both TCP and UDP. It was the login endpoint for QIP, or Quiet Internet Pager, a multiprotocol instant messaging client originally developed by Russian programmer Ilgam Zyulkorneev.1
QIP was enormous in Russia and Eastern Europe through the 2000s. It connected to ICQ's network, supported multiple protocols, and at its peak was one of the most popular messaging clients in the region. In 2008, Russian media company RosBusinessConsulting acquired it.2
Port 2366 handled the login side of that world — the handshake that said "yes, this is you, come in."
The Port Range
Port 2366 falls in the registered port range (1024–49151). This range sits between the well-known ports (0–1023), which are reserved for major protocols like HTTP, SSH, and DNS, and the ephemeral ports (49152–65535), which operating systems assign temporarily for outbound connections.
Registered ports are claimed by applications and services through IANA. The assignment doesn't mean the software is still in use — only that a name was staked here. The IANA registry is more graveyard than phonebook: full of services that once mattered, now quiet.3
Current Status
QIP as an active messaging platform is effectively defunct. The client still floats around in download archives, and the brand exists in some form, but the days of millions of users authenticating through port 2366 are over.
The port remains registered. IANA doesn't reclaim assignments easily — that would risk breaking anything that still depends on the number. So qip-login holds its spot in the registry, a record of something that once needed a door.
If You See Port 2366 Open
If you find port 2366 open on a system today, it's almost certainly not QIP. More likely candidates:
- A developer or legacy application that chose this port arbitrarily
- Malware or unauthorized software using an obscure registered port as cover
- A misconfigured service
Check what's actually listening before assuming the label matches the software.
How to Check What's Using It
On Linux or macOS:
On Windows:
The process ID in the output tells you exactly what's behind the port. Cross-reference it against your running processes to determine whether it belongs there.
Adakah halaman ini membantu?