Port 3029: LiebDevMgmt-A — Liebert's Quiet Watcher

What This Port Is

Port 3029 sits in the registered port range (1024-49151). Ports in this range are assigned by IANA to specific services, but unlike well-known ports (0-1023), they don't require root privileges to bind and carry far less public documentation.

IANA's registry lists port 3029 as LiebDevMgmt-A on both TCP and UDP — a protocol belonging to Liebert Corporation, now operating as Vertiv, a major manufacturer of UPS systems, power distribution units, and thermal management equipment for data centers.¹

The Liebert Device Management Family

Port 3029 is one of three adjacent ports registered under the LiebDevMgmt name:

The suffixes — C, DM, A — suggest different functions within a device management suite, possibly control, data monitoring, and alerting. But that's inference. Liebert never published protocol specifications for these ports.

What Liebert Equipment Actually Does

Liebert builds the infrastructure that data centers depend on when grid power fails. Their UPS systems, power distribution units, and precision cooling equipment are found in server rooms worldwide. Managing that equipment remotely — monitoring battery health, power load, thermal readings, alert thresholds — requires network protocols.

Liebert's modern management interfaces use SNMP, Modbus IP, BACnet IP, and HTTPS through their IntelliSlot network cards.² Whether LiebDevMgmt-A remains in active use on current equipment or was superseded by these standard protocols is unknown from public sources.

Honest Assessment

This port has a name and an IANA registration. Beyond that, the public record is thin. The registration contact is a single individual named Mike Velten. There is no RFC, no public specification, and no documentation of active deployment in any searchable source.

If you see port 3029 active on a network with Liebert or Vertiv equipment, it's almost certainly part of that equipment's management plane. If you see it elsewhere, treat it as unknown and investigate.

How to Check What's Listening

On Linux/macOS:

# Show which process is using port 3029
sudo ss -tlnp sport = :3029
# or
sudo lsof -i :3029

On Windows:

netstat -ano | findstr :3029

Cross-reference the PID with Task Manager or tasklist to identify the process.

Why Unassigned-in-Practice Ports Matter

IANA registration without documentation creates a gap. A port can be "claimed" in a registry with no public accountability for how it actually behaves. That matters for network security: firewall rules, intrusion detection signatures, and vulnerability scanners all benefit from knowing what a port does. When the answer is "something proprietary from a hardware vendor, undocumented," the only honest posture is to verify locally rather than assume.