Squid is a popular caching proxy supporting HTTP, HTTPS, FTP, and other protocols. Squid reduces bandwidth and improves response times by caching and reusing frequently-requested web pages. Squid has extensive access controls and makes a great server accelerator. Squid is often used for content filtering and adaptation. It runs on most available operating systems, including Windows and is distributed under GPL.
Squid Project is an open source project sustained by a community of volunteers distributed around the world. The Squid Software Foundation is a non-profit organization supporting Squid developer and user communities by providing community governance/representation, logistical/administrative assistance, infrastructure resources, and copyright/licensing authority.