DataReel is a free, cross-platform database and communications toolkit. It can be used to rapidly develop and deploy multi-threaded database and communications applications. The DataReel toolkit is composed of a modular C++ library designed to build cross-platform infrastructures for end-user applications, embedded systems, and reusable libraries. DataReel's unique modular design simplifies adaptation, allowing you to determine the level of complexity. DataReel makes Internet connectivity and database programming easy.
Medusa provides a framework for implementing asynchronous socket-based servers for TCP/IP, and on Unix, Unix domain sockets. The first release includes HTTP, FTP, and 'monitor' (remote python interpreter) servers. Medusa can simultaneously support several instances of either the same or different server types - for example you could start up two HTTP servers, an FTP server, and a monitor server. Then you could connect to the monitor server to control and manipulate medusa while it is running.
curl and libcurl is a tool for transferring files using URL syntax. It supports HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP, POP3, IMAP, SMTP, RTSP, RTMP, and FILE, as well as HTTP-post, HTTP-put, cookies, FTP upload, resumed transfers, passwords, port numbers, SSL certificates, Kerberos, and proxies. It is powered by libcurl, the client-side URL transfer library. There are bindings to libcurl for about 40 languages and environments.
libssh is a C library to access SSH services from a program. It can remotely execute programs, transfer files, and serve as a secure and transparent tunnel for remote programs. Its Secure FTP implementation can play with remote files easily, without third-party programs other than libcrypto (from OpenSSL) or libgcrypt.
Secure FTP Factory is a set of Java classes for communicating with FTP servers using the FTP, SFTP (FTP over SSH), and FTPS (FTP over SSL) protocols. The components offer complete FTP functionality, including the ability to transfer files, rename files, delete files, create directories, transfer directories recursively, and more.