Pure-FTPd is a free (BSD), secure, production-quality and standards-conformant FTP server designed with a focus on security, ease of use, and efficiency. It is well-suited for both personal servers and enterprise-grade hosting environments. Pure-FTPd supports a wide range of features, including virtual users, encrypted connections, and detailed logging, making it a robust choice for FTP services.

Features of Pure-FTPd:

• Standards-compliant, secure FTP server designed with a strong focus on software security.
• Supports virtual users and per-user permissions, independent of system users.
• Built-in support for TLS/SSL encryption to protect data in transit.
• Chroot environments to restrict users to their home directories, enhancing security.
• Configurable upload/download bandwidth limits and connection quotas.
• Detailed logging and monitoring support for audit and troubleshooting purposes.
• Open-source software with a permissive license, ensuring free use and modification.

To check the Pure-FTPd version:

 $ apt show pure-ftpd 

Disclaimer: Pure-FTPd is open-source software released under the BSD license. It is developed and maintained by the Pure-FTPd team and contributors. The software is provided "as is", without warranty of any kind, express or implied. Users are responsible for ensuring correct configuration, security, and compliance with all applicable laws and regulations. The developers are not liable for any damages or losses resulting from the use of this software.