Port 3021: Registered, Quiet, and Borrowed by EverQuest 2

What Range This Port Belongs To

Port 3021 is a registered port, sitting in the 1024–49151 range that IANA maintains for software vendors and developers who want a consistent home for their applications. Registered ports don't require root privileges to open (unlike well-known ports below 1024), and they're not ephemeral throwaway numbers (unlike the dynamic range above 49151). They're the middle class of ports: assigned, documented, but not guaranteed to actually be in use.

The Official Tenant: agriserver

IANA lists port 3021 as agriserver — "AGRI Server" — for both TCP and UDP.¹ What is AGRI Server? That's genuinely hard to answer. There's no widely available RFC, no public documentation, and no software project most people would recognize. The name appears in port databases but nowhere else with any weight behind it. It's the kind of registration that exists in the registry and almost nowhere else.

This is more common than you'd think. The registered port range has tens of thousands of entries. Not all of them represent active, maintained software.

The Actual Tenant: EverQuest 2

The software most likely to actually be using port 3021 on a given machine is EverQuest 2, Sony Online Entertainment's 2004 MMORPG. The game's client uses a range of ports including 3016–3021 for game traffic.² If you see activity on port 3021 on a gaming PC, that's the most likely explanation.

This is how the port system works in practice: the registered name is agriserver, but the thing actually listening is a fantasy MMO. The registry is the map. The territory is messier.

How to Check What's Listening

If you see port 3021 open on your machine and you're not playing EverQuest 2:

macOS / Linux:

lsof -i :3021

Windows:

netstat -aon | findstr :3021

Then take the process ID from the output and look it up:

# macOS/Linux
ps aux | grep <PID>

# Windows Task Manager → Details tab, match the PID

Why Unassigned Ports Matter

The registered port range exists to prevent chaos — so that two applications don't accidentally both try to claim port 3021 and collide. In practice, enforcement is light. Software ships, picks a port, and users rarely notice unless two applications conflict. The registry is a courtesy system more than a control system.

When a port is unassigned or has a dormant registration like agriserver, it's available for developers to claim for new projects, or quietly used by existing software that never bothered to register. Neither is wrong. The Internet runs on a surprising amount of informal arrangement.