Squid Cache

Squid Cache started life at the University of California, San Diego in the mid-1990s as the Harvest object cache. It has since grown into a mature, widely deployed open source proxy server that reduces bandwidth and improves response times by caching frequently requested content. Squid runs on most Unix-like systems and on Windows via Cygwin. It supports HTTP, HTTPS, FTP, SSL/TLS, and ICAP for content adaptation. You can configure Squid to act as a forward proxy for internal users, a reverse proxy (accelerator) in front of web servers, or a transparent proxy. It includes access controls, authentication helpers (LDAP, NTLM, Kerberos, basic), traffic management via delay pools, and detailed logging with customizable log formats. Squid can cache DNS lookups and supports ICP, HTCP, and CARP for hierarchical or peer caching. The configuration file (squid.conf) is extensive but well documented. The project is maintained by a community of volunteers and governed by the Squid Software Foundation. A typical setup involves outlining cache size, memory usage, allowed networks, and desired parent peers. For high-traffic sites, Squid can be paired with a web accelerator or load balancer. Many large ISPs and CDN edge nodes have used Squid in production for years.