Port 352: dtag-ste-sb — The Port with Two Names

Port 352 sits in the well-known port range (0-1023), officially assigned by IANA but rarely discussed. It has an unusual characteristic: two documented uses, one official and one unofficial, neither of which most people have ever heard of.

What Runs on Port 352

Officially, port 352 (both TCP and UDP) is assigned to dtag-ste-sb, a service associated with Deutsche Telekom AG (DTAG).¹ The assignment dates back to the early days of the IANA port registry, with contact information listed under Ruediger Wald at Deutsche Telekom.²

What dtag-ste-sb actually does is not well-documented in public sources. The name suggests a Deutsche Telekom-specific service, but details about its protocol or purpose have not been widely published.

The Unofficial Story

Historical IANA records also document an unofficial but widespread use of port 352 for a service called "bhoedap4".¹ This entry was added on May 21, 1997, noting it as "unassigned but widespread use."²

What bhoedap4 was, who used it, and why it was widespread enough to be documented remains unclear. The name doesn't match any well-known protocol or service.

This dual usage—one official assignment coexisting with documented unofficial deployment—is not uncommon in the port registry. It reflects the reality that the Internet doesn't always follow official assignments, especially for services that existed before formal registration processes were fully established.

The Well-Known Port Range

Port 352 belongs to the System Ports (0-1023), also called well-known ports. These ports are assigned by IANA through formal procedures requiring IETF Review or IESG Approval.³

Being in this range means:

• The port was deemed important enough to warrant official assignment
• Services using this port were expected to need privileged access on Unix-like systems
• The assignment is part of the permanent Internet registry

Yet despite this official status, port 352 doesn't appear in common network scanning guides or lists of frequently targeted ports.⁴ It's not SSH, HTTP, or DNS. It's part of the Internet's infrastructure that exists without fanfare.

Why This Port Matters

Port 352 represents the majority of the port space: officially assigned, historically documented, and largely forgotten. Not every port carries millions of connections per second. Not every protocol becomes a household name.

But someone at Deutsche Telekom requested this port assignment. Someone implemented dtag-ste-sb. Someone else deployed bhoedap4 widely enough that IANA documented it. These services existed. They solved problems. They moved data across networks.

The fact that we don't remember them doesn't mean they didn't matter.

Checking What's on Port 352

To see if anything is listening on port 352 on your system:

# On Linux/Mac
sudo lsof -i :352
netstat -an | grep 352

# On Windows
netstat -ano | findstr :352

# Using nmap to scan a remote host
nmap -p 352 hostname

Most systems will show nothing. Port 352 is rarely used in modern deployments. But the registry entry remains, a small monument to services that once ran and may still run somewhere.

Related Ports

• Port 53 (DNS) — Another well-known port assigned to a fundamental Internet service
• Port 179 (BGP) — Routing protocol with official assignment and clear documentation
• Port 443 (HTTPS) — Well-known port that everyone recognizes

Port 352 is part of the Connected project, documenting every port of the Internet. This page last updated February 2026.