Port 325 is unassigned. According to the Internet Assigned Numbers Authority (IANA), it belongs to a block of ports (325-332) that have never been allocated to any protocol or service.1
What This Means
Port numbers are divided into three ranges:
- Well-Known Ports (0-1023): Assigned by IANA, typically requiring IETF Review or IESG Approval. These are the ports for fundamental Internet services—SSH, HTTP, DNS, SMTP.
- Registered Ports (1024-49151): Assigned by IANA with less stringent requirements, used by specific applications and services.
- Dynamic/Private Ports (49152-65535): Not assigned by IANA, used temporarily by client applications or for private services.
Port 325 falls in the well-known ports range. It's officially reserved for future assignment but has never been claimed. When IANA assigns a well-known port, it's because a protocol has been standardized through the IETF process and needs a permanent, globally recognized number. Port 325 never received such a request, or if it did, it wasn't approved.2
Why Unassigned Ports Matter
Not every port number has a service. Out of 1,024 well-known ports, dozens remain unassigned. This isn't neglect—it's deliberate conservation. Once a port is assigned, it's effectively permanent. Protocols live for decades. SSH has used port 22 since 1995. SMTP has used port 25 since 1982.
Unassigned ports are the system's breathing room. They exist for future protocols we haven't invented yet. The next fundamental Internet service will need a number. Maybe it'll be 325.
Checking What's Listening
Even though port 325 is officially unassigned, that doesn't mean nothing could be using it. Any application can listen on any port. To check what's running on port 325 on your system:
On Linux or macOS:
On Windows:
If something appears, it's a custom application or service that chose port 325 precisely because it's unassigned—no conflict with standard services.
The Beauty of Empty Space
There's something honest about port 325. It doesn't pretend to carry anything. It's not SSH or HTTPS or DNS. It's just a number in the registry, available. In a system where almost every slot is spoken for—where 22 means secure shell, where 443 means encrypted web traffic, where 53 means name resolution—port 325 is genuinely empty.
It's been that way since IANA started keeping records. Not every door has a service behind it. Some doors just wait.
Frequently Asked Questions
Was this page helpful?