3Proxy is free tiny cross-platform (Win32/Win64&Unix) proxy servers set. It includes HTTP proxy with HTTPS and FTP support, SOCKSv4/SOCKSv4.5/SOCKSv5 proxy, POP3 proxy, SMTP proxy, AIM/ICQ proxy, MSN messenger / Live messenger proxy, FTP proxy, caching DNS proxy, TCP and UDP portmappers.
You can use every proxy as a standalone program (socks, proxy, tcppm, udppm, pop3p) or use combined program (3proxy). Combined proxy additionally supports features like access control, bandwidth limiting, limiting daily/weekly/monthly traffic amount, proxy chaining, log rotation, syslog and ODBC logging, etc.
It’s created to be small, simple and yet very functional.