What This Port Is
Port 1765 sits in the registered port range (1024–49151), meaning IANA has recorded it, but it isn't a well-known system port. Its official service name is cft-4, part of a contiguous block — ports 1761 through 1768 — reserved for Axway Transfer CFT.
CFT stands for Cross File Transfer. Axway is a French middleware company, and Transfer CFT is their enterprise managed file transfer (MFT) product. It automates point-to-point and point-to-multipoint file exchanges between systems, with built-in security, audit logging, validation, and notification. Think of it as the industrial-grade plumbing that moves payroll files between a bank and its processor at 2am.
The ports 1761–1768 map to internal CFT protocol roles (cft-0 through cft-7), each serving a specific function within the product's communication model. Port 1765 is cft-4. What cft-4 specifically handles internally is not publicly documented in detail — this is enterprise software with enterprise-level opacity. 1
Why Most Databases Say "Unassigned"
The registration exists in IANA's official port registry, but Transfer CFT is niche enough that most third-party port databases either missed the registration or treat the block as practically unused. When you look up port 1765 on general reference sites, you'll often see "unknown" or "unassigned." 2
This is the gap between "officially registered" and "practically known." IANA assigned these ports years ago; the Internet largely forgot.
What the Registered Port Range Means
Ports 1024–49151 are registered ports. Unlike well-known ports (0–1023), you don't need root or administrator privileges to bind to them. Any application can listen here. IANA maintains a registry of registered uses, but registration is voluntary — many applications use ports in this range without any formal registration, and many registered ports are used by software so obscure that the port effectively goes unclaimed in the wild.
If you see traffic on port 1765 and you're not running Axway Transfer CFT, it's worth investigating.
How to Check What's Listening
On Linux or macOS:
On Windows:
Then match the PID to a process name using Task Manager or tasklist.
Why Unassigned Ports Matter
Every open port is a potential entry point. Port scanners like Nmap flag unexpected listeners precisely because "nothing should be here" is meaningful signal. If port 1765 is open on a machine that isn't running Transfer CFT, something put it there — and that's worth understanding.
The registered port range is large enough that gaps are inevitable. Those gaps are where both legitimate software and malicious software tend to hide.
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