Dealing with large IIS log files

IIS captures all page requests made to the server in IIS log file.   There are two areas where the log file can grow quickly, depending on the number of connected users and devices.

You can always disable IIS logging.  Unless there is a need, this is the suggested practice if the web server is located on a secure network.

Please review both sources below which have recommendations on how to resolve.

Source #1:  Push Notification Calls

A majority of LobbyCentral client calls will be to  Request.ashx and Websync.ashx.   Calls are made every 25 seconds which can cause the log file to fill quickly.

Clients such as QMonitor, Kiosk, and end user web clients establish a push notification connection by calling these pages.   Clients attempt to keep the connection open ("alive") by not closing the channel after a request to the server has been made.   After a specific amount of time, the server will run through a list of connections and those that have been opened too long are automatically closed.   When this happens, clients re-establish their connection which results in another call to the server.

Examine the log file and look for entries with request.ashx or websync.ashx.   Lines will look similar to this:

2017-07-18 23:27:08 ::1 POST  /Websync.ashx key=1111111-111-111111-111111&token=13001562&src=js&AspxAutoDetectCookieSupport=1 60521 - ::1 Mozilla/5.0+(Windows+NT+10.0;+WOW64;+Trident/7.0;+Touch;+rv:11.0)+like+Gecko http://localhost/Lobby.aspx 200 0 64 22662

How to Resolve

With  Advanced Logging, you can tell IIS to ignore specific pages by creating a filter. Please see for more information on setting up Advanced Logging.

You can filter the following pages to reduce the size of your log file:

  • Request.ashx
  • Websync.ashx

IIS 7 & 8.0 Users

Advanced Logging is available through the Web Platform Installer.  If you do not have the Web Platform Installer, download it from  here .  Run the Web Platform Installer from inside IIS by clicking "Get new web platform components" link in the Actions pane.  In the Web Platform Installer search box, type advanced logging.  Click Install.

IIS 8.5+ Users

Advanced Logging has been replaced with Enhanced Logging which is built into IIS.

Source #2:  401 Unauthorized Errors

Your log file may also be filling with 401 errors, which means the connection to the web server was not authorized.

This is result of setting up Single Sign-On which requires Windows Authentication and then trying to connect to the push notification service with a non-windows computer or with a computer that is not in the network domain.

Examine the log file and look for entries with a 401 tag:

2017-05-18 00:01:42 POST /servicecenterweb/request.ashx key=11111111-1111-1111-1111-111111111111&token=636276819915850000&src=csc&AspxAutoDetectCookieSupport=1 80 - - http://localhost 401 2 5 12890

If you see this 401 status code (shown in bold italics in the above example), trace the device that is using the IP address (shown in bold in the above example).

When Single-Sign On is enabled, you must set up a secondary anonymous connection site that non-Windows devices can connect to.  For more information on setting up an anonymous site, please review

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