FTP 120 Service Ready Soon vs 551 Page Type Unknown
FTP 120 (Service Ready Soon) is a 1xx Positive Preliminary response, while 551 (Page Type Unknown) is a 5xx Permanent Negative response. 120 indicates that the service will be ready in a certain number of minutes. The server is not yet available but expects to be shortly. In contrast, 551 means that requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
Description
The service will be ready in a certain number of minutes. The server is not yet available but expects to be shortly.
When You See It
When connecting to an FTP server that is starting up or temporarily busy with maintenance tasks.
How to Fix
Wait the indicated number of minutes and try connecting again. If the server never becomes ready, contact the server administrator.
Description
Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
When You See It
When attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
How to Fix
Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.
Key Differences
120 is a 1xx Positive Preliminary response, while 551 is a 5xx Permanent Negative response.
FTP 120: The service will be ready in a certain number of minutes. The server is not yet available but expects to be shortly.
FTP 551: Requested action aborted: page type unknown. The server does not recognize the requested page structure or format.
You encounter 120 when when connecting to an FTP server that is starting up or temporarily busy with maintenance tasks.
You encounter 551 when when attempting a transfer with a page structure type the server does not support. This is extremely rare in modern FTP usage.
When to Use Which
For 120 (Service Ready Soon): Wait the indicated number of minutes and try connecting again. If the server never becomes ready, contact the server administrator. For 551 (Page Type Unknown): Switch to stream transfer mode (MODE S) and file structure (STRU F), which are universally supported by all FTP servers.