FTP Reply Codes
FTP 125 — Data connection already open; transfer starting
In FTP Reply Codes, code 125. The official source describes it as “Data connection already open; transfer starting”. Its concrete cause depends on the operation and surrounding message.
Code125
Symbol—
Source confidencehigh
Official definition
Data connection already open; transfer starting
In plain language
In FTP Reply Codes, code 125. The official source describes it as “Data connection already open; transfer starting”. Its concrete cause depends on the operation and surrounding message.
Context to inspect
- The surrounding operation, version and subsystem determine the actual cause.
- The same numeric value can mean something different in another namespace.
Safe first checks
- Confirm which product, protocol or subsystem produced the code.
- Read the full surrounding error message and inspect relevant logs.
- Compare the code with the linked authoritative documentation before changing configuration.
Important context
The surrounding operation, version and subsystem determine the actual cause.