SOCKS allows to work with any (version SOCKS 4 - with TCP, SOCKS 5 - with TCP and UDP) protocols. A socks proxy simply transfers data from a client to a server, not penetrating into this data contents (therefore it can work with HTTP, FTP, SMTP, POP3, NNTP, etc.).As SOCKS proxies transfer data between computers without changes, it easily allows to create chains of SOCKS proxy servers of arbitrary length. However, for creation of these chains it is necessary to use special programs, as usual software is capable to use only one SOCKS proxy.