Port 3494: IBM 3494 — The Tape Library's Address

What This Port Is

Port 3494 is registered with IANA for the IBM 3494 service — specifically, TCP/IP management communication with IBM's 3494 Enterprise Tape Library. The service name in the IANA registry is ibm3494, registered by Jeffrey Pilch at IBM.

The naming is literal: the port number matches the hardware model number. IBM needed a port for their tape library to communicate over a network, and they chose the obvious one.

What the IBM 3494 Is

The IBM 3494 is an automated tape library — a large robotic system used in enterprise data centers for storing, retrieving, and managing magnetic tape cartridges. These machines are the size of refrigerators (or entire rooms, depending on configuration). A robotic arm moves inside the cabinet, fetching and loading tape cartridges into drives on demand.

They've been used since the 1990s in mainframe environments, large banks, insurance companies, government systems — anywhere that needed to store enormous amounts of data cheaply and durably. Tape doesn't die the way spinning disks do, and it's far cheaper per gigabyte for long-term archival storage.

The library manager communicates over a TCP/IP LAN, receiving commands like "mount this cartridge" or "what's currently loaded?" The host system sends requests; the library manager coordinates the robotic hardware. Port 3494 is where those conversations happen.

The Registered Port Range

Port 3494 lives in the registered port range (1024–49151). These ports require formal IANA registration, but registration doesn't mean the service is commonly deployed — it means someone asked IANA for the number and was granted it. The registered range is a mix of widely-used protocols (like PostgreSQL on 5432), niche enterprise applications, and hardware-specific services like this one.

Most traffic analysis tools will flag port 3494 as "IBM 3494" or "unknown" depending on how current their service database is.

Seeing This Port in the Wild

If you're running a network scan and find port 3494 open, you're almost certainly in or near a mainframe environment. IBM 3494 libraries are not home lab equipment. They're enterprise infrastructure — and the systems that connect to them tend to be equally old-school: IBM mainframes, AIX servers, or legacy Windows systems running IBM tape management software.

Port 3494 appearing on a typical server or workstation would be unusual. It would be worth investigating what's listening.

How to Check What's Listening

On Linux or macOS:

# Show what process has port 3494 open
sudo lsof -i :3494

# Or with ss (modern Linux)
ss -tlnp | grep 3494

On Windows:

# Show listening port and owning process
netstat -ano | findstr :3494

If something responds, the process name will tell you whether it's legitimate IBM tape management software or something else that chose this port.

Security Considerations

Tape library management interfaces are rarely exposed to the public Internet, and port 3494 is not a commonly scanned target. However, in enterprise environments, these management interfaces have historically had weak authentication — they were designed for internal networks where physical security was assumed. Any IBM 3494 management interface reachable from untrusted networks should be treated with caution.

Related Ports

• 3495 — Also associated with IBM tape library functionality in some configurations
• 1494 — Citrix ICA (unrelated, but frequently confused in documentation that mislabels 3494)
• 2598 — Citrix Session Reliability (the actual Citrix session port sometimes incorrectly attributed to 3494)