Link Check Monitor

The SiteScope Link Check Monitor checks the internal and external links on a Web page to insure that they can be reached. SiteScope begins checking links from a URL that you specify, verifies that linked graphics can be found, and follows HREF links to the referenced URL's. The monitor can be configured to check all of the links on your site or limited to a specified number of "hops".

In addition to checking the links, a Link Report is created. This report can be viewed by choosing the Summary link in the More column. The report displays all the links checked, the status of each link, size, estimated download time via a 28.8 connection, and the page containing the link. You may reorder the entries in this table by clicking on the column heading that you want the entries to be sorted by. For example, if you want the entries to be sorted by retrieval time, click the Time column heading.

Each time the Link Check Monitor runs, it returns a status and writes it in the monitoring log file. It also writes the total number of broken links, the total number of links, the total number of graphics, and the average time for retrieving a page.

Usage Guidelines

There is nothing more frustrating for your Web site visitors than trying to follow a broken link. Ensuring that your site is free of broken links is something that everyone knows they should do, but it is often the thing that gets moved to the bottom of the to-do list. This monitor can be set to check every link on your site, internal and external, every day, letting you know immediately which links have a problem.

What to monitor

You should monitor the Web site for the availability of key content. This includes checking that image files and linked HTML files are accessible as referenced within the Web pages. Starting with your home page, the Link Check Monitor will branch out and check every link available on your entire site by default. If you only want it to check a portion of your site, specify the URL that links into the targeted area. You can limit the number of linked "hops" the monitor will follow in the Advanced Options section. Even if you are not the person responsible for Web content, you can set the monitor to run once a day and have the alerts e-mailed directly to your Web content developer.

About scheduling this monitor

You probably only need to run the link monitor once a day to check for external links that have been moved or no longer work and internal links that have been changed. You can also run it on demand any time you do a major update of your Web site.

Completing the Link Check Monitor Form

To display the Link Check Monitor Form, either click the Edit link for an existing Link Check Monitor in a monitor table, or click the add a Monitor link on a group's detail page and click the Add Link Check Monitor link.

Complete the items on the Link Check Monitor form as follows. When the required items are complete, click the Add Monitor button.

URL: Enter the URL that will be the starting point for checking links (for example, http://demo.thiscompany.com). The link monitor will retrieve the page for this URL. Next, it will read the URLs for any links on the page. It will continue until it has checked all of the links on the site. Links to other servers will be checked but it will not continue and check all the links of those other servers.
Update every: Select how often the monitor should check this URL. The default interval is to run or update the monitor once every 10 minutes. Use the drop-down list to the right of the text box to specify another update interval in increments of seconds, minutes, hours, or days. The update interval must be 15 seconds or longer.
Title: Enter a title text for this monitor. This text is displayed in the group detail page, in report titles, and other places in the SiteScope interface. If you do not enter a title text, SiteScope will create a title based on the host, server, or URL being monitored.

Advanced Options

The Advanced Options section presents a number of ways to customize monitor behavior and display. Use this section to customize error and warning thresholds, disable the monitor, set monitor-to-monitor dependencies, customize display options, and enter other monitor specific settings required for special infrastructure environments. The options for this monitor type are described below. Complete the entries as needed and click the Add or Update button to save the settings.

Disable

Check this box to temporarily disable this monitor and any associated alerts. To enable the monitor again, clear the box.

Pause

The delay, in milliseconds, between each link check. Larger numbers will lengthen the total time to check links but will decrease the load on the server.

Maximum Links

The maximum number of links this monitors will check. When the maximum is reached the monitor will stop running. Increase this number if you have a large site and want to check every page on the site.

Maximum Hops

The maximum number of internal links that SiteScope should follow from the starting URL. For example, if you set the number of hops to three, SiteScope will check all internal pages that can be reached within 3 clicks from the starting URL. Limiting this number will reduce the number of URLs that SiteScope follows, shortening the time to complete the report. SiteScope will not follow any links on external pages.

Timeout

The number of seconds that the URL monitor should wait for a page to begin downloading before timing-out. Once this time period passes, the URL monitor will log an error and report an error status.

HTTP Proxy

Optionally, a proxy server can be used to access the URL. Enter the domain name and port of an HTTP Proxy Server.

Authorization User Name

If the URL specified requires a user name for access, enter the name in this box.

Authorization Password

If the URL specified requires a password for access, enter the password in this box.

Proxy Server User Name

If the proxy server requires a name to access the URL, enter the name here. Technical note: your proxy server must support Proxy-Authenticate for these options to function.

Proxy Server Password

If the proxy server requires a password to access the URL, enter the password here. Technical note: your proxy server must support Proxy-Authenticate for these options to function.

Post Data

Enter any form values required for the first page being checked. This is useful if you need to log in via an HTML form to reach the rest of the site that you are checking.

Verify Error

Check this box if you want SiteScope to automatically run this monitor again if it detects an error. When an error is detected, the monitor will immediately be scheduled to run again once.

Note: In order to change the run frequency of this monitor when an error is detected, use the Update every (on errors) option below.

Note: The status returned by the Verify Error run of the monitor will replace the status of the originally scheduled run that detected an error. This may cause the loss of important performance data if the data from the verify run is different than the initial error status.

Warning: Use of this option across many monitor instances may result in significant monitoring delays in the case that multiple monitors are rescheduled to verify errors at the same time.

Update Every (on error)

You use this option to set a new monitoring interval for monitors that have registered an error condition. For example, you may want SiteScope to monitor this item every 10 minutes normally, but as often as every 2 minutes if an error has been detected. Note that this increased scheduling will also affect the number of alerts generated by this monitor.

Schedule

By default, SiteScope monitors are enabled every day of the week. You may, however, schedule your monitors to run only on certain days or on a fixed schedule. Click the Edit schedule link to create or edit a monitor schedule. For more information about working with monitor schedules, see the section on Schedule Preferences for Monitoring.

Monitor Description

Enter additional information about this monitor. The Monitor Description can include HTML tags such as the <BR> <HR>, and <B> tags to control display format and style. The description will appear on the Monitor Detail page.

Report Description

Enter an optional description for this monitor that will make it easier to understand what the monitor does. For example, network traffic or main server response time. This description will be displayed on with each bar chart and graph in Management Reports and appended to the tool-tip displayed when you pass the mouse cursor over the status icon for this monitor on the monitor detail page.

Depends On

To make the running of this monitor dependent on the status of another monitor or monitor group, use the drop-down list to select the monitor on which this monitor is dependent. Select None to remove any dependency.

Depends Condition

If you choose to make the running of this monitor dependent on the status of another monitor, select the status condition that the other monitor or monitor group should have in order for the current monitor to run normally. The current monitor will be run normally as long as the monitor on which it depends reports the condition selected in this option.

List Order

By default, new monitors are listed last on the Monitor Detail page. You may use this drop-down list to choose a different placement for this monitor.

Error if

By default, SiteScope generates an error if there are any broken links. You may choose to generate an error based on broken links, total pages, total graphics, or average retrieval time. Enter a comparison value and use the comparison operator list to specify an error threshold such as: >= (greater than or equal to), != (not equal to), or < (less than).

Warning if

By default, SiteScope does not generate warnings for Link Check monitors. You may choose to generate a warning based on broken links, total pages, total graphics, or average retrieval time. The symbols in the comparison value list are the same as for the Error if condition.

Good if

By default, this monitor returns a good reading if all links can be retrieved. You can change this to be dependent upon total pages, total graphics, or average retrieval time. Select the option you want from the drop-down list and then set the desired threshold. The symbols in the comparison value list are the same as for the Error if condition.