netkit-ftp

ftp [options] [host [port]]

-v
    Enables verbose mode, displaying all server responses.

-d
    Turns on debugging, printing debugging information.

-i
    Turns off interactive prompting during multiple file transfers (e.g., with mget or mput).

-n
    Suppresses auto-login upon initial connection, requiring manual user and pass commands.

-g
    Disables filename globbing, preventing special characters from being expanded into a list of filenames.

-p
    Enables passive mode, which is often necessary when the client is behind a firewall or Network Address Translation (NAT).

-k
    Disables TCP keep-alive messages on the control connection.

-A
    Immediately attempts an anonymous login when a host is specified.

netkit-ftp is a traditional command-line client for the File Transfer Protocol (FTP), used for transferring files between a local host and a remote FTP server. It provides a basic yet powerful interface for navigating remote directories, uploading files (put), downloading files (get), listing contents (ls, dir), and managing files on the server.

While it lacks modern features like SFTP or FTPS for secure transfers, it remains a fundamental tool for interacting with plain FTP servers. Its simplicity makes it suitable for scripting basic file transfer operations or for environments where secure FTP protocols are not available or required. It operates by establishing a connection, authenticating the user, and then allowing interaction through a set of internal commands.

Security Risk: netkit-ftp transfers credentials (username/password) and all data in plaintext, making it highly vulnerable to eavesdropping and interception. It is not suitable for sensitive data.
No SFTP/FTPS: It does not support secure variants of FTP like SFTP (FTP over SSH) or FTPS (FTP over SSL/TLS), which provide encryption.
Firewall Challenges: Active mode FTP can struggle with firewalls and NAT configurations. While passive mode (-p option) helps, complex network setups can still pose connectivity challenges.
Limited Features: Lacks advanced features found in modern FTP clients, such as transfer resume capabilities, advanced scripting options, or robust error handling for large-scale operations.

Once connected to an FTP server, netkit-ftp provides a rich set of interactive commands for file operations and server interaction. These are distinct from command-line options and are executed within the FTP prompt:

• get: Download a file from the server to the local machine.
• put: Upload a file from the local machine to the server.
• ls / dir: List directory contents on the remote server.
• cd / cdup: Change the current directory on the remote server.
• lcd: Change the current working directory on the local machine.
• mget / mput: Download/upload multiple files using globbing patterns.
• ascii / binary: Set the file transfer mode (ASCII for text files, Binary for all other files).
• delete / mkdir / rmdir: Delete a file, create a directory, or remove a directory on the server.
• bye / quit: Close the FTP connection and exit the client.
• help / ?: Display help for available commands.

netkit-ftp is part of the broader netkit package, which historically provided a collection of fundamental networking utilities for Unix-like operating systems. It represents an older, widely adopted implementation of the standard FTP client, having been a ubiquitous tool in Unix/Linux environments for many years before more feature-rich or secure alternatives gained prominence. Its design reflects the common FTP usage patterns and protocol specifications prevalent in the early days of the internet, emphasizing basic command-line interaction.

sftp(1): Secure File Transfer Program (via SSH)., lftp(1): Sophisticated command-line FTP/HTTP/FXP client., wget(1): Non-interactive network downloader., scp(1): Secure copy (remote file copy program)., ncftp(1): User-friendly FTP client with advanced features.