Port 3500: Unassigned — Claimed in Practice

What This Port Is

Port 3500 sits in the registered port range (1024–49151). IANA maintains this range as a registry where software vendors and protocol authors can claim a port number and formalize its use. Port 3500 has no such claim — IANA lists it as unassigned.

That doesn't mean it's quiet.

Known Unofficial Uses

SAP Business Objects Data Services (BODS)

The most widespread use of port 3500 is SAP's data integration platform. SAP Data Services defaults its Job Server to port 3500, with ports 3500–3599 reserved for job server communication in multi-instance deployments. Anyone running SAP BODS will find this port in their firewall rules, often opened bidirectionally between client and server.¹

EMC AlphaStor

EMC AlphaStor's Library Manager runs a service called robotd on port 3500. In 2008, a vulnerability in this service (CVE-2008-2157) allowed remote attackers to execute arbitrary commands via a crafted packet — a reminder that obscure services on unassigned ports still get exploited.²

Security: CVE-2024-52544

In late 2024, a critical vulnerability was disclosed for a DP Service listening on TCP port 3500. An unauthenticated attacker could trigger a stack-based buffer overflow remotely. The issue was patched in firmware version 2.800.0000000.8.R.20241111.³

This is the quiet danger of unassigned ports: no community awareness, no default scrutiny, no expectation that anything important is there — which is exactly why attackers look.

Why Unassigned Ports Matter

The IANA registry exists so that port numbers carry shared meaning. When software skips registration and squats on an unassigned port, a few things break:

• Collision risk. Two pieces of software might independently choose the same port. On a machine running both SAP BODS and EMC AlphaStor, port 3500 is contested.
• No documentation trail. Administrators who find traffic on port 3500 have to guess what it is.
• Security blindspots. Scanners and firewalls often treat unassigned ports as lower priority.

The registered port range has over 48,000 ports. Most remain unclaimed. Software fills them informally, and the gap between practice and registry grows wider every year.

How to Check What's Using Port 3500

macOS / Linux:

# Show the process listening on port 3500
sudo lsof -i :3500

# Or with ss
ss -tlnp sport = :3500

Windows:

netstat -ano | findstr :3500
tasklist | findstr <PID>

Cross-platform (nmap):

nmap -sV -p 3500 localhost

If you find something listening here unexpectedly, lsof or netstat will show you the process name and PID. From there, you can trace it to its executable.