Proxy Server Products

There are a number of web proxy servers available. These are the most commonly used software packages:

• Squid. Open source Squid is the de facto standard at universities. It is free, reliable, easy to use and can be enhanced (for example, adding content filtering and advertisement blocking). Squid produces logs that can be analyzed using software such as Awstats, or Webalizer, both of which are open source and produce good graphical reports. In most cases, it is easier to install as part of the distribution than to download it from www.squid-cache.org (most Linux distributions such as Debian, as well as other versions of Unix such as NetBSD and FreeBSD come with Squid). A good Squid configuration guide can be found at squid-docs.sourceforge.net/latest/book-full.html.

• Microsoft Proxy server 2.0. Not available for new installations because it has been superseded by Microsoft ISA server and is no longer supported. It is nonetheless used by some institutions, although it should perhaps not be considered for new installations.

• Microsoft ISA server. ISA server is a very good proxy server program, that is arguably too expensive for what it does. However, with academic discounts it may be affordable to some institutions. It produces its own graphical reports, but its log files can also be analyzed with popular analyzer software such as Sawmill. Administrators at a site with MS ISA Server should spend sufficient time getting the configuration right; otherwise MS ISA Server can itself be a considerable bandwidth user. For example, a default installation can easily consume more bandwidth than the site has used before, because popular pages with short expiry dates (such as news sites) are continually being refreshed. Therefore it is important to get the pre-fetching settings right, and to configure pre-fetching to take place mainly overnight. ISA Server can also be tied to content filtering products such as WebSense. For more information, see: www.microsoft.com/isaserver and www.isaserver.org.