Free and fast proxy checking software.

Features
Check SOCKS4/SOCKS5/HTTP/HTTPS proxies with and without authentication.
Format of proxies with authentication: proxy_user:proxy_pass@proxy_host:proxy_port.
Format of proxies without authentication: proxy_host:proxy_port
Check for connect to the specified host:port.
Check for URL.
Load and combine proxies without checking.
Multithreaded.
Handle redirects.
Download proxy lists from the web.
Customizable User Agent.
Customizable HTTP Headers (Accept, Accept-Encoding).
Built-in proxy distribution web server.
Proxy country detection.
RBL (DNSBL) check.