FTP (File Transfer Protocol) is a standard network protocol used to transfer files from one host to another over a TCP-based network such as the Internet. Debugging FTP connections can be crucial when troubleshooting connectivity issues or ensuring data is transferred correctly. Windows provides built-in tools to help with this process, primarily through the Command Prompt.

Examples:

Using Command Prompt for FTP Debugging

1. Open Command Prompt:

   • Press Win + R, type cmd, and press Enter.

2. Start FTP Session:

   • In the Command Prompt, type ftp and press Enter to start the FTP client.

3. Enable Debug Mode:

   • Type debug and press Enter. This command enables debugging, which will display all commands and server responses during the FTP session.

4. Connect to an FTP Server:

   • Use the command open [hostname] to connect to the FTP server. Replace [hostname] with the server's address.
   • Example: open ftp.example.com

5. Login:

   • Enter your username and password when prompted.

6. Transfer Files:

   • Use commands like get [filename] to download a file or put [filename] to upload a file.
   • Example: get example.txt

7. Observe Debug Output:

   • As you execute commands, observe the detailed output provided by the debug mode. This includes command execution and server responses, which can help identify where issues may be occurring.

8. Close the FTP Session:

   • Type bye or quit to close the session.

Example Session:

C:\> ftp
ftp> debug
Debugging On .
ftp> open ftp.example.com
Connected to ftp.example.com.
220 Welcome to Example FTP Server
User (ftp.example.com:(none)): myusername
331 Password required for myusername
Password:
230 User myusername logged in
ftp> get example.txt
---> TYPE I
200 Type set to I
---> PORT 192,168,1,100,14,178
200 PORT command successful
---> RETR example.txt
150 Opening BINARY mode data connection for example.txt (1024 bytes)
226 Transfer complete
ftp> bye
221 Goodbye.

Additional Tips:

• Passive Mode: If you encounter issues with active mode, try switching to passive mode using the passive command. This can help with firewall and NAT traversal issues.
• Verbose Mode: Use the verbose command to toggle verbose mode, which provides additional information about the FTP session.