Port 3656: ActiveBatch Job Scheduler — The Enterprise Automation Port

What Runs on Port 3656

Port 3656 is registered to ActiveBatch Job Scheduler, service name abatjss. ActiveBatch is an enterprise workload automation platform made by Redwood Software (originally ASCI — Advanced Systems Concepts). The registration dates to January 2003. ¹

ActiveBatch has a three-tier architecture: a Windows-based Job Scheduler, cross-platform Execution Agents, and a client console. Port 3656 is where the Job Scheduler listens. When a client triggers a job or an agent reports results, that communication goes through this port. ²

What ActiveBatch Actually Does

Enterprise environments run thousands of scheduled jobs: database backups, ETL pipelines, report generation, file transfers, compliance checks. Without workload automation, each of these lives in its own scheduler — Windows Task Scheduler, cron, whatever the application ships with — and no single person knows the full picture.

ActiveBatch pulls all of that into one place. You define workflows, set dependencies, handle failures, and track everything from a single console. The Job Scheduler on port 3656 is the coordinator — it knows what needs to run, what's running, and what ran.

Who Uses This Port

You won't encounter port 3656 on a personal machine or a small-team web server. This port lives in enterprise data centers, on Windows Server machines running workload automation for banks, manufacturers, healthcare systems, and logistics companies. The kind of places where "the batch jobs didn't run last night" is a serious incident.

ActiveBatch competes with Control-M, Tivoli, and Autosys — the workhorses of enterprise IT that most developers never touch, but that keep large organizations running.

Port Range Context

Port 3656 falls in the registered ports range (1024-49151). This range is administered by IANA. Unlike the well-known ports (0-1023), registered ports don't require elevated privileges to bind, and they cover a vast middle ground of commercial software, internal tools, and infrastructure components. ³

How to Check What's Listening

If you see traffic on port 3656 and want to confirm what's using it:

Linux/macOS:

sudo ss -tlnp | grep 3656
sudo lsof -i :3656

Windows:

netstat -ano | findstr :3656
Get-Process -Id (Get-NetTCPConnection -LocalPort 3656).OwningProcess

If you're on a Windows Server and see port 3656 active, there's a good chance ActiveBatch Job Scheduler is running. That's expected and intentional — it means someone configured workload automation on that machine.

Security Notes

Port 3656 should not be exposed to the public Internet. ActiveBatch is internal enterprise infrastructure. If you find port 3656 open on a system you didn't expect, ask whether ActiveBatch was intentionally installed. Unauthorized job schedulers are a lateral movement risk — they can execute arbitrary commands on a schedule.

Firewall rules for ActiveBatch should restrict port 3656 to known clients: the console machines and Execution Agents that legitimately communicate with the Job Scheduler. ⁴