Port 3095: Panasas Rendezvous — The Meeting Point for Supercomputer Storage

Port 3095 is assigned to Panasas as a rendezvous port for their PanFS parallel file system. IANA registered it on 2017-08-17 for both TCP and UDP.¹

If you've never heard of Panasas, that's expected. They build storage infrastructure for high-performance computing — the kind used in national labs, genomics research, oil and gas exploration, and supercomputing centers. Their PanFS file system allows thousands of compute nodes to read and write simultaneously at speeds that would make a standard NAS system collapse.²

What a Rendezvous Port Does

In distributed systems, a rendezvous port is the designated meeting point — the address clients contact first to discover where they should go next.

Think of it like a host stand at a restaurant. You don't sit down wherever you want. You check in at the front, get assigned a table, and then the real interaction begins. Port 3095 plays that role: clients knock here, the system coordinates, and then connections are directed to wherever they need to go.

The specific internal mechanics of Panasas's rendezvous protocol aren't publicly documented, but the pattern is common in distributed storage and messaging systems. Coordination happens first at a known address; data movement happens after.

Who Actually Uses This Port

In practice, port 3095 appears in environments running PanFS — which means university research clusters, government computing centers, and HPC facilities in industries with massive data workloads. If you're not in one of those environments, this port is irrelevant to your infrastructure.

One other notable appearance: the UDP range 3074–3174 is used by Rainbow Six Vegas for multiplayer matchmaking, which technically overlaps with port 3095 UDP. Gaming traffic and supercomputer storage are unlikely to share a network, but it's worth knowing if you're inspecting firewall logs and seeing unexpected UDP activity on this port.³

Checking What's on This Port

If port 3095 shows up on a system you're responsible for, a few commands will tell you what's using it:

Linux/macOS:

# Show which process is listening on port 3095
ss -tlnp | grep 3095

# Or with lsof
lsof -i :3095

Windows:

# Show process using port 3095
netstat -ano | findstr :3095

If you're running Panasas storage, seeing this port active is expected. If you're not, investigate — an unexpected listener on any registered port deserves attention.

Why Registered-but-Obscure Ports Matter

The registered port range (1024–49151) contains over 48,000 possible ports. IANA manages assignments, but registration doesn't mean universal recognition. Many security tools, firewall rulesets, and network monitoring systems treat registered ports as "known safe" without checking whether the actual assignment matches expectations.

Port 3095 is a good example of the gap between "registered" and "well-known." It has a legitimate owner and a real purpose — but that purpose only matters in a narrow set of environments. Everywhere else, an active listener on this port is something to examine.