Port 707: Borland DSJ — A ghost from Java's deployment past

Port 707 carries the official assignment for Borland DSJ (Deployment Server for Java), a deployment service that was part of JBuilder, Borland's integrated development environment for Java.¹²

The software it served is long gone. The port number remains.

What DSJ Was

In the late 1990s and early 2000s, Borland Software Corporation was a major player in development tools. JBuilder was one of the leading Java IDEs of its era, competing with tools from IBM, Sun, and others.³

DSJ—Deployment Server for Java—was the component responsible for deploying Java applications from the IDE to servers. Developers would build their applications in JBuilder, then use DSJ to push them out to production or test environments. It needed its own port because deployment was a separate service, running independently of the IDE itself.

The process worked like this: JBuilder would compile your Java code, package it, and then communicate with DSJ over port 707 to transfer and deploy the application. DSJ handled the server-side logistics—placing files, configuring environments, starting services.

Why It Exists

Port 707 was assigned during an era when Java deployment was complicated and vendor-specific. Every IDE vendor had their own deployment tools. Borland had DSJ. IBM had its own solutions. Sun had others.

This was before:

• Standardized application servers with unified deployment mechanisms
• Build tools like Maven and Gradle that automated deployment
• Cloud platforms that abstracted deployment entirely
• DevOps practices that treated deployment as code

In that world, a dedicated deployment service made sense. It needed a port. IANA assigned 707.

What Happened

Borland sold its development tools division to CodeGear in 2006. Embarcadero Technologies acquired CodeGear in 2008.³ JBuilder continued for a while but gradually lost market share to free alternatives like Eclipse and IntelliJ IDEA.

DSJ disappeared along with the deployment model it served. Modern Java deployment happens through:

• Application servers with standardized deployment APIs
• Container orchestration platforms like Kubernetes
• Cloud platform tools (AWS, Azure, Google Cloud)
• CI/CD pipelines that treat deployment as automation

You will almost never see port 707 in use on a modern network. The software that claimed it is obsolete. But the IANA assignment persists—a permanent record that this port once served a real purpose.

Security Considerations

If you see port 707 open on a modern system, it's worth investigating. Either:

• Someone is running very old Borland software (unlikely and concerning from a security perspective)
• Another service is using the port unofficially
• Something malicious is masquerading on an obscure assigned port

Old development tools like JBuilder and DSJ are not receiving security updates. Running them on a network is dangerous.

The Well-Known Range

Port 707 sits in the well-known port range (0-1023), also called system ports. These ports are assigned by IANA and historically required root/administrator privileges to bind to on Unix-like systems.

Getting a well-known port assignment meant your service was significant enough to warrant permanent, privileged allocation. Borland was important enough in the 1990s to receive that assignment.

The well-known range is mostly full now. Most new services get registered ports (1024-49151) or use dynamic ports (49152-65535). Port 707 is a reminder of when assignment criteria were different and the Internet's infrastructure was still being defined.

Checking What's Listening

To see if anything is listening on port 707 on your system:

Linux/Mac:

sudo lsof -i :707
sudo netstat -tlnp | grep :707

Windows:

netstat -ano | findstr :707

You can also use nmap to scan for port 707 on remote systems:

nmap -p 707 target-ip

If you find something listening and you're not running ancient Borland software, investigate further.

Related Ports

Borland's development ecosystem used other ports for different services. The broader Borland Enterprise Server (later Borland Application Server) used various ports for CORBA communication, management interfaces, and other services.⁴

Modern Java application servers typically use:

• 8080 - HTTP for Tomcat, JBoss (default development port)
• 9080 - WebSphere Application Server HTTP
• 7001 - WebLogic Server (default)
• 8009 - AJP connector for Tomcat

These replaced the fragmented deployment model that DSJ represented.

Why Unassigned Ports Matter

Port 707 is assigned, but barely used—a ghost port. The broader well-known range contains many such ports: services that were once important but have faded into obsolescence.

These ghost ports matter because:

1. They're historical markers - They show what was once significant enough to warrant permanent assignment
2. They can be repurposed maliciously - Obscure assigned ports are attractive to malware because security tools may not expect traffic there
3. They represent opportunity cost - Each obsolete assignment is a well-known port number that can't be used for something current

IANA rarely revokes port assignments, even when the service disappears. Port 707 will likely remain "borland-dsj" forever, even though DSJ itself is gone.

The Lesson

Port 707 is a reminder that the Internet's infrastructure carries permanent marks of its history. Services come and go. Companies rise and fall. But port assignments persist.

Somewhere in IANA's registry, Borland DSJ is still listed at port 707. The software doesn't run anymore. The company that built it has been through multiple acquisitions. The deployment model it served has been replaced entirely.

But the port number remains—a small monument to a specific moment in software history, when deploying Java applications was complicated enough to need its own service, and Borland was important enough to receive a well-known port for it.