Using Web Proxy Filters

From the January 2009 Issue

A web proxy filter is a server or series of servers located between two computers — the computer making the request for a website and the computer that provides the content of the website. These devices monitor the information flowing between the two computers, which are connected to the proxy. The proxy will make and receive requests from either of the computers and will fulfill those requests. The proxy machine provides a separation between the two computers and prevents direct connections between them.

The Benefits of Web Proxy Filters Web proxy filters are a new service that allows for your web traffic to be monitored and checked for malware. As more and more e-mail viruses utilize the web or components on the web to infect computers, this service is growing in importance and is becoming another tool in the arsenal to protect your data from business continuity interruptions due to malware.

Third-party web proxy filters are generally billed for as a monthly per-user fee. The costs are fairly reasonable at only a few dollars per user per month. Most service providers range between $1 and $5 dollars per user.

How Does a Web Proxy Filter Work?
Web proxy filters are generally purchased from third parties who provide the proxy service. You simply direct all the web traffic to the proxy by entering the proxy server information in the browser of choice. When a user goes to a website, the information requested goes to the provider’s proxy. The proxy receives the request and forwards the request on to the website being requested while substituting its information for the return connection. The website being requested sends back the information requested to the proxy, which checks it for malicious content before sending it on to the requesting user.

This process applies to all Internet requests including downloads and ActiveX controls. The proxy server looks for content that contains harmful code and malware. Since both incoming and outgoing is checked, it also prevents any malware in your offices on your computers from spewing from your network to the Internet. The outbound traffic is redirected to the proxy for filtering, too.

In addition to filtering for malware, many of these services offer the ability for the firm to set acceptable viewing/use standards. You could block political or shopping websites from the list of acceptable sites that a user can visit. When the user attempts to access one of these sites, they will be blocked from doing so and receive a message showing that the filtering service has blocked the site. Each service categorizes website content into various categories and then blocks that content if selected for blocking to prevent employees from accessing the content.