By Rob Bilson, Contributing Editor

Anyone who has surfed the Web can relate to the frustration of encountering a broken link. There are few things users hate more than clicking through to a promising resource, only to receive the famous "404 Document Not Found" error. For those who manage corporate Intranets, broken links can mean the difference between closing a major deal and losing user confidence and support. Users expect and require consistent access to relevant information, lest the corporate web become yet another frustrating computer system -- not exactly the route to a healthy return on investment.

Enter Linkbot 3.0 from Ottawa-based Tetranet Software Inc. Linkbot is a high-performance site management tool that makes finding and fixing broken links easy. Using so-called spider technology, the software crawls an Intranet or Internet web , following and testing each link it encounters. Linkbot 3.0 distinguishes itself from other tools in its class by incorporating a high speed multi-tasking engine. With the ability to check up to 20 URLs simultaneously, Linkbot 3.0 can make quick work ou t of any site management task. In addition to checking for broken links, Linkbot 3.0 is capable of locating missing images and stale content, identifying orphaned files, and finding pages with slow download times.

Installing Linkbot 3.0 was a straightforward process that took less than five minutes. The program is capable of running on any Windows 95/NT machine with access to the site that is to be analyzed. Tetranet adheres to the paperless school of software do cumentation; the box contains no user manual, but I found the online help at least as complete as many books. The product also comes with a well designed HTML-based tutorial that steps the user through a series of 13 exercises, each revealing a key featur e.

Linkbot 3.0 sports a clean, intuitive user interface, with the majority of functions available from the main toolbar. (Screen shot at left.)

Following the tutorial, I decided to put Linkbot through its paces in a production environment, running it under Windows 95 on a Pentium 133 with 32 MB RAM -- a typical client today, even on the shy side processor-wise The Intranet site I tested resides on a P166 with 216 megs RAM running NT 4.0 sp3 and IIS 3.0. The connection between the computer running Linkbot and the test site was over a 4 MB/s token ring LAN.

Site insight

The first step was to get Linkbot to scan the site for the first time, a simple matter of entering its URL into the program's "Address" box. To test Linkbot's performance, I repeated this step twice with two different configurat ions, each time performing a series of trials.

The first series was conducted with Linkbot's multitasking engine set to use 20 concurrent connections, the maximum supported. I performed 3 trials, with the results listed in the table below. (Formatted as shown at right.)

For the second series of trials, I decreased the number of concurrent connections to 10. While this slowed performance, Linkbot still scanned the entire site in under 3 minutes - not bad for a site containing over 2000 links.

Once Linkbot finishes checking a site, users are given the option of viewing the results within Linkbot's "Explorer" like interface or as an HTML report. Using the Linkbot interface, users can toggle among any one of six views allowing them to see the UR L tree, broken links, pages referencing broken links, old pages, slow loading pages, and orphaned pages. (See example at left.) Within each of these views, any combination of 13 filters can be applied to help administrators visualize and organize the results into meaningful groups. Once you have identified all of problem pages, you can modify them using your authoring tool or, convenient for simple fixes, Linkbot's built-in HTML editor.

Flexible flyer

Besides being fast, Linkbot 3.0 is fully customizable. Because administrative policies and maintenance procedures differ from site to site, Linkbot provides an array of flexible configuration options. For instance, the software allows you to customize t he criteria for several of its scanning functions, from setting the depth of a site search (i.e., number of levels to follow links), to defining the file size that flags a "slow" download. A cute feature lets you specify how old documents have to be befor e they are considered stale. For those making use of site analysis tools, Linkbot allows you to set the HTTP user agent to any number of options for enhanced tracking.

In addition, Linkbot 3.0 fully supports proxy servers as well as secure (SSL) pages. It even allows you to specify user names and passwords for accessing controlled pages, useful for unattended scans. Of course, if you do this you'll want to contro l access to Linkbot itself.

Linkbot 3.0 comes with an advanced scheduling feature that allows the program to be run unattended at predetermined instances. This allows administrators to run Linkbot at off-peak times when server traffic is presumably light. Users can specify w here Linkbot should begin scanning as well as what file reports should be saved to. Linkbot can be scheduled to run just once or on a repeating schedule such as every hour or every Tuesday at 6pm. When Linkbot has finished a scheduled scan, it closes its elf down, freeing up system resources.

The Bottom Line

Linkbot 3.0 is an accomplished, feature-rich product that every Webmaster should consider adding to his or her toolkit. I especially like its ability to schedule unattended scans, which goes a long way towards automating one of an administrator's least fu n, but most important, tasks: making sure the links work.

Linkbot 3.0 comes in two versions: Linkbot Standard and Linkbot Pro. Both versions can be purchased through Tetranet's Web site or resellers. The Pro version retails for $199.95 and contains all the features discussed in this review. Linkbot Standard goes for $99.95 and is ideal for personal web checking, lacking Pro's support for proxies, password authentication, built-in scheduling, and orph an analysis.

>Rob Bilson is a freelance writer and the Senior Webmaster at Amkor Electronics, the global leader in semiconductor IC packaging, assembly and test. In addition, he can of ten be found doing consulting work for the Hard Drive Cafe, a Delaware based Internet/Intranet consulting firm.