If you have ever worked in a network load balanced (NLB) environment with multiple SharePoint front end servers, you have no doubt had at least one occasion where only some of your users were seeing some sort of strange behavior. Perhaps some users receive a generic error message when accessing a page and others do not. Whatever the reason, it never hurts to be able to have users give you just a little bit more information to help you in the troubleshooting process.
Of course, you can always dig through the ULS log files on each front end server to look for any anomalies or to match up correlation ID values associated with generic error messages. But wouldn’t it be great if your end user could tell you that he or she is hitting front end #3 so you don’t have to waste time searching through the logs on front ends #1 and #2 first?
One potential solution to this problem (and there are no doubt more elegant ways to solve it) are to create multiple images such as the ones below:
Save each image with exactly the same name (such as frontend.jpg) and place it in the TEMPLATE\IMAGES directory of the SharePoint root on each front end (make sure you match up the correct image with each front end server!) Then, when something goes wrong for one user but not another, you can ask him/her to visit the following URL:
Based on the number that appears, you will know exactly which front end that user is hitting!
I hope this information is useful to you. You could extend this by creating a custom URL action called “Front End Check” that allows certain users to hit the front end image link directly without having to remember it. Feel free to leave your thoughts and suggestions in the comments!