Port 2546: Unassigned — The EVault Squatter

What Port 2546 Is

Port 2546 sits in the registered port range (1024–49151) — the space IANA set aside for applications to claim through a formal registration process. Nobody claimed it. IANA lists it as unassigned for both TCP and UDP.

That doesn't mean it's been idle.

The EVault Connection

EVault — a backup and disaster recovery platform originally from i365, later acquired by Seagate, and eventually absorbed into IBM as IBM Cloud Backup — used port 2546 for communication between its backup agents and vault servers.¹

The agent is the software running on the machine being backed up. The vault is the server receiving the backup data. Port 2546 was the channel between them, with legacy fallback support on port 807.²

EVault never formally registered the port with IANA. They just used it. This is more common than you'd think — plenty of real-world software occupies ports without the paperwork.

If you're running IBM Cloud Backup (the current name for this product line), you may still encounter port 2546 in firewall documentation.

Registered but Unregistered

The registered port range exists so organizations can officially stake a claim: "This port belongs to our application." The process involves submitting to IANA with a service description and contact information.

Port 2546 skipped that step. It's in the range, it's been used commercially, but it carries no official record. This matters practically: there's no authoritative documentation of what should be listening here, which makes it harder to distinguish legitimate EVault traffic from something unexpected.

Checking What's on This Port

If port 2546 shows up on your network, here's how to investigate:

On Linux/macOS:

# See what process is listening on port 2546
sudo lsof -i :2546

# Or with ss (modern systems)
ss -tlnp | grep 2546

On Windows:

netstat -ano | findstr :2546
# Then look up the PID in Task Manager

Network-wide:

nmap -sV -p 2546 <target>

If you see something listening on 2546 and you're not running EVault or IBM Cloud Backup, it's worth investigating. There's no legitimate widely-used service assigned here.