CAS Server and Using and Troubleshooting IIS Log Files

Hosting web pages through server software is becoming a very necessary thing to do for most organizations. While renting out space in a hard drive from a hosting company’s server may reduce some of the technical skills required to get up and running, it doesn’t allow you the flexibility that comes with operating your own server.

This article will briefly go over the configuration benefits of having your own setup to do what you want; namely, providing an overview of central authentication service (CAS) and showing how to use and troubleshoot internet information service (IIS) log files.

CAS Server

CAS is a single sign on protocol that many organizations (namely Universities) are employing to allow users to gain access to all or allowed web applications/resources from the user’s credentials–i.e. a single sign on.

The benefits of this are convenience for the user in having access to web applications without having to re-type it multiple times; therefore, providing a seamless user experience as different web resources are traversed without pause. Also, security is another benefit of having this service on your network, since user credentials aren’t stored in a central location. This means that if a web application is compromised, the threat won’t have access to other applications via user credentials.

IIS Log Files

The log files that come integrated with IIS for Windows server provide tracking and usage data about the server. This can be leveraged to enable server admins the ability to analyze particular categories of data, such as the IP address of users, the queries that are used on websites, and regional data as well. This kind of information is invaluable to improving the user experience and providing better services for traffic via performance testing.

The following sections will go over how to locate your log files, how to use them for performance testing, and troubleshooting some issues with them.

Locating your Log Files

Finding the log files on your server is pretty easy:

  1. Run the IIS software by going to Start > All Programs > Administrative Tools > Internet Information Services (IIS).
  2. Navigate to your web site, located on the left pane, right-click it, and choose Properties.
  3. Make sure that you are on the Web site tab and locate the the section labeled “Active Log Format” and click on the Properties button in that section.
  4. Now, ensure that you are in the General Properties tab and locate the box that contains the log file directory and log file name. Use these items to locate the log file in the directory.

Using the Log Files for Performance Testing

Now that you’ve located your log files, its time to do perform some analysis on them. This section will go over briefly how to measure the performance of your site.

There are 3 steps in analyzing log files. The first begins with setting it up. As it is already integrated with IIS, this step is more of a starting point rather than an actual step. Now that the log files are already set up, you can perform some sort of test, such as a stress test. After doing this, parse the logs with LogParser software and analyze the results.

Troubleshooting Log Files

This section will go over some common issues relating to log file errors:

  • If you are unable to create a log file for any reason, typically you’ll need to check the security settings between the log file and the directory that it is saved to.
  • If the system can’t write to a log file then the problem is either the a full disk and additional space is required to write more data or a problem in the network which prevents the program from writing to a log file.
  • If the system refuses to write to a log file, then this normally means that a log file is already created in the directory but the system can’t verify the user that has access to the log files.

Some other problems arise if you have more than one server that you’d like to pull log files from. In the event that you get log files from one server, but are unable to get log files from another, then check the following:

  1. Are you able to access other data from the server? If not, then it might be a bigger problem, but perhaps more easily remedied.
  2. Is there a barrier preventing only some data from coming in? Then chances are that it is a firewall problem.

Use the following points in this section as a guide to troubleshooting log file errors.


CAS and IIS are both great programs to use in conjunction when running your own server. This article briefly went over CAS and its benefits; also, we touched upon the significance of log files and how you can use them to perform analysis and what to do when they give out errors.

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