When are the parameters used in WebResource.axd reset?

Question

When using WebResource.axd you will see two parameters being passed in the query string. Usually looks something like this:

WebResource.axd?d=9H3mkymBtDwEocEoKm-S4A2&t=634093400273197793

I have run into an issue where I need a permanent link to the resource in question. Recently the link I was using stopped working. What would cause these ids to change? Rebooting the server? Recompiling the code? Is there anyway to make these ids permanent?

Background -

As part of a site monitoring service we are subscribed to, we have "recorded" several sets of user actions for our website. For example, we recorded the process of logging into the site. The monitoring is now saying that the user login process fails (it's working fine) because it cannot find the WebResource.axd with the ids it recorded.

Answer 1

This page provides all the information on the makeup of the URL

http://support.microsoft.com/kb/910442

The "d" stands for the requested Web Resource

Something worth noting is that you don't need to have the timestamp (t) parameter there to call the resource. Try it on your own site, view the source and grab a webresource.axd url and navigate to the it, remove the t