Port 3338: anet-b — ABB Industrial Control Data

What This Port Is

Port 3338 sits in the registered port range (1024–49151) — the middle tier of the port number system. IANA has assigned it the service name anet-b, described as "OMF data b."

That label means something specific: this port is used by ABB's Aspect Server, a core component of their System 800xA distributed control system (DCS). System 800xA is what runs industrial facilities — power plants, paper mills, refineries, chemical plants. The Aspect Server is the communication backbone that lets operators query and control physical equipment from software interfaces.

OMF here stands for Object Management Framework — ABB's architecture for treating every piece of industrial equipment as a software object with queryable properties. Port 3338 (anet-b) carries one category of that object data. Its siblings handle others:

If you work in industrial IT or operational technology (OT) security, these ports look familiar. If you don't, you'll likely never encounter traffic on them.

Who Should See This Port Open

In a legitimate ABB System 800xA deployment, port 3338 will be open on Aspect Server nodes and the machines that communicate with them. It should be firewalled off from anything that isn't part of the control system network. Industrial control systems (ICS) and operational technology (OT) networks are meant to be air-gapped or tightly segmented from general enterprise networks.

If you see port 3338 open on a general-purpose server, a home router, or anything outside an industrial automation context — that's worth investigating.

How to Check What's Listening

On Linux or macOS:

ss -tlnp | grep 3338
# or
lsof -i :3338

On Windows:

netstat -ano | findstr :3338

The process ID in the output can be matched to an application in Task Manager (Windows) or ps aux (Linux/macOS).

Why the Registered Range Works This Way

The registered port range exists for applications that need a consistent, known port but don't have the universality of well-known services like HTTP or DNS. IANA registers these on request — an organization says "we use port X for service Y," submits the paperwork, and it goes into the registry.

The result is a range full of legitimate but obscure assignments: industrial protocols, enterprise software, legacy systems, proprietary communication layers. Most ports in this range are quiet on most machines. The registry entry documents what should be there, not what is there on any given system.

Port 3338 is a good example: legitimately assigned, used in real infrastructure, and invisible to almost everyone.

Security Notes

Some older security databases flag port 3338 as historically associated with malware activity. This is common for ports in this range — when malware authors pick ports to blend in or avoid firewalls, registered-but-obscure ports are attractive. The association appears to be historical and non-specific; no widely documented active threat currently targets 3338 as a primary channel.

The more relevant concern is its legitimate use in OT/ICS contexts: industrial control system ports exposed to untrusted networks are a serious attack surface. ABB System 800xA networks should be treated as critical infrastructure and segmented accordingly.