ISPPlanet Cache Review Series - Quantex WebXL

Configuring Cache Services
WebXL can cache HTTP 1.0, HTTP 1.1, HTTP/FTP and HTTP/Gopher content, including .exe, Java applets, and cookies. Although WebXL does not cache news or video, Novell cached streamed multimedia at the QuickTime Live! conference in November and expects to add this to NICS version 2 next year. The WebXL supports SSL tunnels and clams to handle up to 100,000 persistent connections, avoiding constant re-establishment to yield better performance and efficiency.

GUI Cache panels are used to configure Client and Server Acceleration services, WebXL Clusters, URL Filtering, scheduled Downloads, cache Bypasses, and Tuning. Client Acceleration defines the port and IPs that accept forward-proxied traffic, enumerates ports that will be transparently-proxied, and source IPs that are exempt from transparent proxying. We had difficulty successfully testing Exception IPs; Quantex is investigating the problem. Client Logging specifies whether client requests are logged, maximum log size for roll-over, and how long the log files are retained.

Web Server Acceleration creates virtual server on a specified port at one or more WebXL interfaces, redirecting traffic to a list of back-end servers. Logging can be selectively enabled for each virtual server. This allows several physical servers to share dynamic workload, while the WebXL vends static content. But it does not configure back-end heuristics (e.g., weighting, busyness) that enable true load balancing. Acceleration also eliminates site outages when a single server fails.

Because our back-end test servers hosted static (cacheable) content, all requests after the first were served up by the WebXL.

The WebXL can be configured to block requests to specified URLs with the Filter / Override feature. Alternatively, purchase a URL Filtering subscription from partners XSTOP or N2H2. We tested this feature with a 30-day free trial from XSTOP. Simply add the service name, login, (visible!) password, and XSTOP URL to the Filter panel. A new filter list is automatically uploaded on a scheduled basis. Content categories are used to configure red-light (deny) or green-light content.

We found blocking unrated traffic of little use since most "good" sites are not (yet) self-rated. Overrides allow sites that would otherwise be blocked. Optional logs record filtered traffic, but do not identify requesting clients. Our filters worked as configured, with one significant exception: during reconfiguration, we experienced a GUI error, followed by odd WebXL behavior that blocked all traffic and required a hard restart. Quantex and XSTOP believe that a loss of configuration or packet during filter download caused this problem.