gFTP is a free multithreaded file transfer client for *NIX based machines running X11R6 or later. It has text and GTK+ 1.2/2.x interfaces and supports the FTP, FTPS (control connection only), HTTP, HTTPS, FSP, and SSH protocols and has FTP and HTTP proxy server support. It supports UNIX, EPLF, Novell, MacOS, VMS, MVS, and NT (DOS) style directory listings, and has a bookmarks menu that allows you to quickly connect to remote sites. The code is fully internationalized and there are currently 45 translations available.
wzdftpd is designed to be a small, efficient, and highly modular/configurable FTP server for various platforms including Linux and Windows. The server is RFC compliant, multi-threaded and can be configured entirely online using SITE commands. You can write your own extensions to the server in your choice of language, extending on existing MySQL, PostgreSQL, SQLite, Tcl, Perl, PAM, and SFV plugins. Features include IPv6, TLS/SSL, UTF8, ACLs, VFS, events, scripting, plugins, job scheduler, bandwidth limitations, credits/sections, group administration, and customizable logging.
Net::FTPServer is a full-featured, secure, extensible, and highly configurable FTP server which can serve files from a standard file system or a relational database. It is written in Perl, which provides natural protection against buffer overflows. It has feature parity with popular C-based servers such as wu-ftpd. The server offers virtual hosts (IP-based and experimental IP-less). It is configurable in Perl, for both small Perl "hacks" in the configuration file all the way up to complete server "personalities". It supports the latest RFCs and Internet Drafts. Authentication may be done through /etc/passwd, PAM or an authentication plug-in. Resource limits are supported. The server may run standalone or from inetd. chroot() jails are supported along with sophisticated programmable access control rules. All aspects of server use and configuration are comprehensively documented in a manual running to some 50 pages.
BSDftpd-ssl is a secure and easy-to-use FTP server that supports industry standard TLS/SSL encryption and authentication for whole FTP sessions and data transfers. This implementation supports both the original FTP protocol and the RFC2228-compliant TLS/SSL enhancement. The package contains the secure FTP server (named "ftpd") and a command line TLS/SSL-aware FTP client (named "ftps"). The server's features include logging of transfers, changing of a session root (known as "chroot"), and virtual host support.
libcurl.mono is an object-oriented binding for the libcurl Internet client API. It supports rapid-development of powerful Internet clients in C# that can run within the mono runtime. With libcurl.mono, for example, you can develop FTP and HTTP clients without having to code down at the socket level. There are a number of sample applications to get you started.