Port 2394: MS OLAP 2 — A Microsoft Legacy Port

What This Port Is

Port 2394 is a registered port — meaning it sits in the range from 1024 to 49151, where IANA tracks assignments made by vendors and developers. Unlike well-known ports (0–1023), registered ports don't require special operating system privileges to open, and their assignments are advisory rather than enforced.

IANA lists port 2394 as ms-olap2 on both TCP and UDP — a registration made by Microsoft for OLAP Services 7.0, an early analytical database product that shipped in the late 1990s as part of SQL Server 7.0.

The History

Microsoft shipped OLAP Services 7.0 in 1998 alongside SQL Server 7.0. It was one of the first mainstream tools for OLAP — Online Analytical Processing, the engine behind pivot tables and data cubes that let businesses slice sales figures by region, quarter, and product category. Two ports were registered: 2393 (ms-olap1) and 2394 (ms-olap2). ¹

When SQL Server 2000 arrived, Microsoft rebranded OLAP Services as Analysis Services and gave it a new default home: port 2383. Ports 2393 and 2394 remained available for backward compatibility with older clients, but the center of gravity had shifted. ²

Today, SQL Server Analysis Services runs on port 2383 by default, and ports 2393 and 2394 are largely dormant — present in the IANA registry as a record of software history more than active infrastructure. ³

Who Might Still Use It

Very few systems. You might encounter traffic on port 2394 on:

• Old SQL Server 7.0 installations that were never upgraded (rare but not impossible in long-running enterprise environments)
• Legacy applications built specifically against OLAP Services 7.0 that hardcoded these ports
• Firewall rules written in 1999 that nobody has touched since

If you're seeing unexpected traffic on 2394 in a modern environment, it's worth investigating — it's not a port that legitimate modern software uses by default.

Checking What's Listening

To see whether anything is using port 2394 on your system:

Linux / macOS:

# Show process listening on port 2394
ss -tlnp | grep 2394

# Or with lsof
lsof -i :2394

Windows:

netstat -aon | findstr :2394

The last column in the Windows output is the process ID. Cross-reference it with Task Manager or:

tasklist /fi "PID eq <process_id>"

What Unassigned (and Abandoned) Ports Reveal

Port 2394 isn't truly unassigned — it's assigned to something that no longer dominates. This is actually common in the port registry. Of the 49,151 registered ports, hundreds belong to products that were discontinued, renamed, or superseded. IANA doesn't reclaim them; the registry only grows.

This matters for two reasons. First, security: a port with a legitimate-sounding historical registration can be used by malware or unexpected services precisely because defenders may assume it's "fine." Always verify what's actually listening, not just what the registry says should be there. Second, archaeology: the port registry is a timeline of software history — each number a timestamp of when some engineer decided their protocol deserved a permanent address.

Port 2394 is a registration from 1998 that outlived its reason for existing. The Internet keeps its receipts.