If you are looking for a free network library for the .NET platform then you may wish to look at BytesRoad.NetSuit library. This is an open source network library completely written in C#. You may find it useful if you would like to insert support for communication with FTP servers in your application. FTP support implemented in the library is very powerful as it is compliant with RFC 959 (File Transfer Protocol) and includes the ability to communicate with FTP servers through the various proxies (such as Socks4, Socks4a, Socks5, HTTP CONNECT). The capability of communication with FTP servers though the proxies depends on another set of classes exposed by the library. You may also use these classes in your application to implement low level network communication with remote computers through the proxies.