Web cache

A Web cache (or HTTP cache) is a system for optimizing the World Wide Web. It is implemented both client-side and server-side. The caching of multimedia and other files can result in less overall delay when browsing the Web.^[1]^[2]

Parts of the system

Forward and reverse

A forward

HTTP options

The

Legality

In 1998, the Digital Millennium Copyright Act added rules to the United States Code (17 U.S.C. §: 512) that exempts system operators from copyright liability for the purposes of caching.

Server-side software

This is a list of server-side web caching software.

Name	Operating system			Forward mode	Reverse mode	License
Name	Windows	Unix-like	Other	Forward mode	Reverse mode	License
Apache HTTP Server	Yes	OS X, Linux, Unix, FreeBSD, Solaris, Novell NetWare	OS/2, TPF, OpenVMS, eComStation	Yes		Apache 2.0
aiScaler Dynamic Cache Control	No	Linux	No			Proprietary
ApplianSys CACHEbox	No	Linux	No			Proprietary
Blue Coat ProxySG	No	No	SGOS	Yes	Yes	Proprietary
Nginx	Yes	Linux, BSD, OS X, Solaris, AIX, HP-UX	Yes	Yes	Yes	2-clause BSD-like
Microsoft Forefront Threat Management Gateway	Yes	No	No	Yes	Yes	Proprietary
Polipo	Yes	OS X, Linux, OpenWrt, FreeBSD	?	Yes	Yes	MIT License
Squid	Yes	Linux	?	Yes	Yes	GPL
Apache Traffic Server	?	Linux	?	Yes	Yes	Apache 2.0
Untangle	No	Linux	No	Yes	Yes	Proprietary
Varnish	No	Linux	No	Needs a VMOD	Yes	BSD
WinGate	Yes	No	No	Yes	Yes	Proprietary (Free for 8 users)
Nuster	No	Linux	No	Yes	Yes	GPL
McAfee Web Gateway	No	McAfee Linux Operating System	No	Yes	Yes	Proprietary

References

^ Fountis, Yorgos (4 May 2017). "How does the browser cache work?".
^ Messaoud, S.; Youssef, H. (2009). "An analytical model for the performance evaluation of stack-based Web cache replacement algorithms". International Journal of Communication Systems. 23: 1–22. doi:10.1002/dac.1036. S2CID 46507769.