Squid is a high-performance proxy caching server for web clients, supporting FTP, gopher, and HTTP data objects. Unlike traditional caching software, Squid handles all requests in a single, non-blocking, I/O-driven process.
Squid keeps meta data and especially hot objects cached in RAM, caches DNS lookups, supports non-blocking DNS lookups, and implements negative caching of failed requests.
Squid supports SSL, extensive access controls, and full request logging. By using the lightweight Internet Cache Protocol, Squid caches can be arranged in a hierarchy or mesh for additional bandwidth savings.
Squid consists of a main server program squid, a Domain Name System lookup program dnsserver, a program for retrieving FTP data ftpget, and some management and client tools. When squid starts up, it spawns a configurable number of dnsserver processes, each of which can perform a single, blocking Domain Name System (DNS) lookup. This reduces the amount of time the cache waits for DNS lookups.
Squid is derived from the ARPA-funded Harvest project.
Internet object caching is a way to store requested Internet objects (i.e., data available via the HTTP, FTP, and gopher protocols) on a system closer to the requesting site than to the source. Web browsers can then use the local Squid cache as a proxy HTTP server, reducing access time as well as bandwidth consumption.
Harris' Lament says, ``All the good ones are taken."
We needed to distinguish this new version from the Harvest cache software. Squid was the code name for initial development, and it stuck.
Squid is updated often; please see the Squid home page for the most recent versions.
Squid is the result of efforts by numerous individuals from the Internet community. Duane Wessels of the National Laboratory for Applied Network Research (funded by the National Science Foundation) leads code development. Please see the CONTRIBUTORS file for a list of our excellent contributors.
You can download Squid via FTP from the primary FTP site or one of the many worldwide mirror sites.
Many sushi bars also have Squid.
The software is designed to operate on any modern Unix system, and is known to work on at least the following platforms:
For more specific information, please see platforms.html. If you encounter any platform-specific problems, please let us know by sending email to squid-bugs.
Recent versions of Squid will compile and run on Windows/NT with the GNU-Win32 package.
However, Squid does not yet perform well on Windows/NT.
We also have a few other mailing lists which are not strictly Squid-related.
Several Squid and Caching-related web pages are available:
Squid can proxy SSL requests. By default, Squid will forward all SSL requests directly to their origin servers. In firewall configurations, Squid will forward all SSL requests to one other proxy, defined with the ssl_proxy directive.
Squid is copyrighted by the University of California San Diego and Duane Wessels. Squid uses some code developed by others.
Squid is Free Software.
Squid is licensed under the terms of the GNU General Public License.
We think so. Squid uses the Unix time format for all internal time representations. Potential problem areas are in printing and parsing other time representations. We have made the following fixes in to address the year 2000:
Yep. The following companies will support Squid for you:
We provide commercial Squid support; we frequently deploy squids in caching proxy, transparent caching proxy, httpd accelerator, and hierarchical modes, for a wide variety of corporate and public sector clients, including members of the Fortune 500. Inquires can be directed to FSC Information.
If you know someone who takes money for supporting Squid, let us know and we will add their information here.
The following people have made contributions to this document:
Please send corrections, updates, and comments to: squid-faq@ircache.net.
This document is copyrighted (1998) by Duane Wessels and the National Laboratory for Applied Network Research
This document was written in SGML and converted with the SGML-Tools package. This document is available in both HTML and compressed Postscript.