Port 3424: xtrms — Xware xTrm over SSL/TLS

What Port 3424 Does

Port 3424 carries the Xware xTrm Communication Protocol over SSL/TLS, registered with IANA under the service name xtrms. It is the encrypted version of port 3423, which runs the same protocol without encryption.

Xware was an enterprise integration and EDI (Electronic Data Interchange) middleware company. Their xTrm protocol handled structured B2B transactions — purchase orders, invoices, logistics updates — between large enterprise systems. Port 3424 is where those transactions traveled when they needed to be encrypted in transit.

If you see traffic on port 3424, it almost certainly belongs to Xware middleware or a system built on top of it, not general-purpose traffic.

The Port Range

Port 3424 falls in the registered ports range (1024–49151). These ports are:

• Not reserved for privileged services (unlike well-known ports below 1024)
• Registered with IANA by organizations that want a stable, official assignment
• Not enforced — any application can bind to any registered port, IANA registration is advisory, not policed

The registration means Xware formally claimed this number to avoid conflicts with other software. Whether your system uses it for anything is a separate question.

Checking What's on This Port

If you see port 3424 active and you didn't put it there:

# macOS / Linux — show what process is listening
sudo lsof -i :3424

# Linux alternative
ss -tlnp | grep 3424

# Windows
netstat -ano | findstr :3424
# Then look up the PID:
tasklist | findstr <PID>

If nothing appears, the port isn't in use. If something appears, the process name will tell you whether it's legitimate.

Port 3423 and 3424 as a Pair

Ports 3423 and 3424 are a matched pair — a pattern common in protocol design:

This mirrors how HTTP (80) and HTTPS (443) relate to each other. The s suffix denoting the SSL/TLS variant is a naming convention that shows up throughout the registered port list.¹

Why Obscure Ports Like This Exist

Most registered ports belong to products you've never used. Enterprise middleware, industrial control systems, legacy financial software — they all needed stable port numbers to function, and IANA provided them. The registry holds thousands of these assignments.

This matters for a practical reason: when you're securing a system, the registered ports range isn't a safe zone. Any port in 1024–49151 might be in use by something, intentionally or accidentally. The IANA registry is a reasonable first stop when you encounter unfamiliar traffic.²