Port 768 sits in the well-known port range (0-1023)—the section of the port number space that IANA reserves for system-level services and standardized protocols. But when you look up port 768 in the official registry, you find nothing. No assigned service. No protocol. Just an empty entry in what's supposed to be the Internet's most carefully managed address space.
What Unassigned Means
The port number space is divided into three ranges:1
- Well-known ports (0-1023): System ports assigned by IANA for standard protocols
- Registered ports (1024-49151): User ports that can be registered with IANA for specific services
- Dynamic/private ports (49152-65535): Ephemeral ports used for temporary connections
Port 768 is in the first category—a well-known port—but it has no official assignment. IANA typically only records assigned and reserved port numbers in the registry.1 Unassigned ports exist in the gaps between official services, available for future assignment but not currently spoken for.
The Ghost of RPC Past
While port 768 has no official service name, it does have a history. Older Linux distributions occasionally used ports in the 512-1024 range for RPC (Remote Procedure Call) services.2 Port 768 sometimes appeared as an rpc.mountd port—the mount daemon that handles NFS file system mount requests.
On Mac OS X systems, port 768 was associated with NetInfo and other RPC-based administrative services.3 These were implementation choices by operating system vendors, not standardized protocols. Different systems used the same port number for different purposes, which is precisely the chaos that IANA port assignments are supposed to prevent.
Why This Matters
Unassigned ports in the well-known range are unusual. This range exists for a reason—to provide stable, predictable port numbers for protocols that need universal recognition. When you see HTTP traffic, you expect port 80. When you see HTTPS, you expect port 443. These assignments are the foundation of how the Internet routes application-layer traffic.
An unassigned well-known port is a missed opportunity for standardization. It also creates potential security concerns. Since there's no standard service for port 768, any traffic on this port should be investigated.2 It could be legitimate legacy RPC traffic from an old system. It could also be unauthorized access attempts or malware using an obscure port to avoid detection.
How to Check What's Listening
To see if anything is using port 768 on your system:
On Linux or macOS:
On Windows:
If you find something listening on port 768, investigate what process owns it. The process ID (PID) will tell you what's running. Legitimate uses are rare. Most modern systems have no reason to bind to this port.
The Pattern of Unassigned Ports
Port 768 is not alone. The well-known port range has dozens of unassigned numbers scattered between the official services. Some of these gaps exist because IANA assigns ports in response to requests—there's no master plan to fill every number. Some exist because older services were deprecated and their port numbers were released back into the unassigned pool.
These empty seats in the registry represent the evolution of the Internet. Protocols come and go. Standards change. The port number space preserves room for future protocols we haven't invented yet, alongside relics of protocols that didn't survive.
Port 768 is one of these relics—used occasionally by specific implementations, but never standardized, never given an official name, never claimed by a protocol that needed universal recognition. It's a reminder that not every port number tells a story. Some are just empty space, waiting.
Frequently Asked Questions About Port 768
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