The following table provides a list of the possible reply codes returned by an FTP server.
| 110 | Restart marker reply. |
| 120 | Service ready in nnn minutes. |
| 125 | Data connection already open; transfer starting. |
| 150 | File status okay; about to open data connection. |
| 200 | Command okay. |
| 202 | Command not implemented, superfluous at this site. |
| 211 | System status, or system help reply. |
| 212 | Directory status. |
| 213 | File status |
| 214 | Help message. |
| 215 | NAME system type. |
| 220 | Service ready for new user. |
| 221 | Service closing control connection. |
| 225 | Data connection open; no transfer in progress. |
| 226 | Closing data connection. |
| 227 | Entering Passive Mode (h1,h2,h3,h4,p1,p2). |
| 230 | User logged in, proceed. |
| 250 | Requested file action okay, completed. |
| 257 | "PATHNAME" created. |
| 331 | User name okay, need password. |
| 332 | Need account for login. |
| 350 | Requested file action pending further information. |
| 421 | Service not available, closing control connection. |
| 425 | Can't open data connection. |
| 426 | Connection closed; transfer aborted. |
| 450 | Requested file action not taken. File unavailable (e.g., file busy). |
| 451 | Requested action aborted: local error in processing. |
| 452 | Requested action not taken. Insufficient storage space in system. |
| 500 | Syntax error, command unrecognized. |
| 501 | Syntax error in parameters or arguments. |
| 502 | Command not implemented. |
| 503 | Bad sequence of commands. |
| 504 | Command not implemented for that parameter. |
| 530 | Not logged in. |
| 532 | Need account for storing files. |
| 550 | Requested action not taken. File unavailable (e.g., file not found, no access). |
| 551 | Requested action aborted: page type unknown. |
| 552 | Requested file action aborted. Exceeded storage allocation (for current directory or dataset). |
| 553 | Requested action not taken. File name not allowed. |
.NET: net5.0, net5.0-windows, net6.0, net6.0-macos, net6.0-windows, net7.0, net7.0-macos, net7.0-windows, net8.0, net8.0-browser, net8.0-macos, net8.0-windows, net9.0, net9.0-browser, net9.0-macos, net9.0-windows, net10.0, net10.0-browser, net10.0-macos, net10.0-windows.
.NET Standard: netstandard2.0, netstandard2.1
.NET Framework: net20, net35, net40, net403, net45, net451, net452, net46, net461, net462, net463, net47, net471, net472, net48, net481.