Port 1440: Eicon Service Location Protocol — Where telecom servers announce themselves

What Runs on Port 1440

Port 1440 is officially registered with IANA for eicon-slp (Eicon Service Location Protocol), a service discovery protocol used by Eicon Networks' telecommunications products.¹²

When a Diva Server or other Eicon device starts up on a network, it uses port 1440 to announce what services it provides—voice, fax, ISDN connectivity, conferencing capabilities. Client applications can query port 1440 to discover these services without knowing the server's IP address in advance.

This is service location: the protocol that lets devices find each other by asking "what can you do?" instead of needing a hardcoded map.

How It Works

Service location protocols solve a fundamental networking problem: how do you find a service when you don't know where it lives?

The traditional answer is manual configuration—someone writes down IP addresses and port numbers in configuration files. But Eicon's approach was automatic discovery:

1. Advertisement: Eicon servers broadcast or respond to requests on port 1440, announcing their capabilities
2. Discovery: Client applications send queries to port 1440 asking "who provides ISDN services?"
3. Connection: Once discovered, clients connect to the actual service ports on the server

The Service Location Protocol (SLP) was standardized in RFC 2608,³ but Eicon developed their own variant (eicon-slp) specifically for their telecommunications product line, including the Diva Server systems used for voice, fax, and ISDN connectivity.⁴

The Eicon Context

Eicon Networks Corporation, founded in 1984, built telecommunications adapters and servers—hardware that connected computer networks to traditional phone systems.⁵ Their Diva Server line handled T1/E1 lines, ISDN, SS7 signaling, and conventional phone lines (PSTN).

In the 1990s and early 2000s, when these systems were widely deployed, you might have dozens of Diva Servers scattered across a corporate network, each providing different capabilities. Port 1440 let management software automatically discover and inventory these servers without maintaining manual lists.

Eicon was eventually acquired by Dialogic Corporation, and the product line continues under the Dialogic brand.⁶

Current Usage

Port 1440 is rarely seen in modern networks. The Diva Server product line still exists but serves a shrinking market—most voice infrastructure has moved to VoIP and SIP rather than traditional ISDN and PSTN connectivity.

If you encounter traffic on port 1440, you're likely looking at:

• Legacy Eicon/Dialogic telecommunications hardware still in production
• Older enterprise voice systems that haven't been upgraded
• Specialized telecom environments that still use ISDN or T1/E1 connectivity

Security Considerations

Service discovery protocols can leak information about network infrastructure. An attacker scanning port 1440 can enumerate:

• What Eicon/Dialogic servers exist on the network
• What capabilities each server provides
• Potential targets for further exploitation

Best practice:

• Block port 1440 at your firewall unless you actively use Eicon/Dialogic equipment
• Restrict eicon-slp traffic to VLANs where the servers actually operate
• Monitor for unexpected traffic on this port as a potential reconnaissance indicator

Checking What's Listening

To see if anything is listening on port 1440 on your local machine:

Linux/Mac:

sudo lsof -i :1440
netstat -an | grep 1440

Windows:

netstat -ano | findstr :1440

If something is listening and you don't have Eicon/Dialogic telecommunications equipment, investigate further.

Related Ports

Port 1440 exists in the context of other service discovery mechanisms:

• Port 427 - Service Location Protocol (SLP) v2, the standardized version
• Port 5353 - mDNS (Multicast DNS), used by Bonjour and similar modern discovery protocols
• Port 1900 - SSDP (Simple Service Discovery Protocol), used by UPnP

Each solves the same problem—how do devices find services without manual configuration—but for different ecosystems and eras.

Why This Port Matters

Port 1440 represents a specific moment in networking history: when enterprises ran their own telecommunications infrastructure and needed automated ways to manage it.

The broader lesson is timeless: service discovery remains essential. The protocols change—eicon-slp gave way to SLP, which gave way to mDNS and DNS-SD—but the fundamental question persists: "What services exist on this network, and how do I find them?"

Port 1440 carries the answer for one particular family of telecommunications servers. Most networks will never use it. But for those that do, it's the difference between automatic discovery and manual inventory maintenance.

That quiet background announcement—"I'm here, this is what I do"—is what makes networks manageable at scale.