Using Squid to filter Internet access
The Internet Content Adaptation Protocol (ICAP) was designed for transparent web proxies to query an external service as to whether or not a request should be served. It is most commonly used for content filtering and anti-virus scanning.
This approach does have some challenges, though. For example, when using SquidClamav  to tie the ClamAV scanner into your Squid server, you might encounter timeouts on clients, because the entire file must be downloaded and scanned before it is served to the client; it cannot be scanned on the fly and served to the client using SquidClamav. So, although this approach will work well for smaller files, it may cause problems with larger files. The other downside of ICAP is that although a few ICAP servers are available, there are very few good content sources (e.g., malicious URLs) that you can feed into your ICAP service.
I have strong feelings (mostly pro) about unfiltered and unlimited Internet access, but I also recognize that blocking the bad stuff (spammers, ad servers, tracking cookies, etc.) will generally make for a less annoying and better Internet experience. Additionally, certain user communities (e.g., children) should not have unfiltered access, whereas other groups might need filtered access for legal reasons. As a final note, much like a firewall, having a web proxy can allow you to detect malicious incoming and outgoing traffic and block it, thus preventing problems from getting bigger.
- "Squid in the Middle" by Kurt Seifried, Linux Magazine, October 2012: http://www.linux-magazine.com/Issues/2012/143/HTTPS-Proxy
- Squid: http://www.squid-cache.org/
- Squid Config Examples: http://wiki.squid-cache.org/ConfigExamples
- SquidClamav: http://squidclamav.darold.net/
Buy this article as PDF
Upcoming switch to HTML5-only ads is further evidence the Flash is entering its final days.
US government invests $19 billion on enhancing security and replacing ancient computer systems.
But you can still be a non-voting “individual supporter” if you pay the money
Several current systems could fall victim to the attack
Latest Linux engine comes with better graphics and support for Intel's new power-saving chips.
Hackers send a message of beauty and liberation to server logs
Citrix gets excited about new Pi-Powered XenDesktop client system
Linux on Azure cert heralds a new era for Redmond.
Proposals for presentations at the CeBIT Open Source Forum will be accepted through 24 January 2016.
Adobe looks for a new start; renames its embattled Flash tool.