SharePoint 2010 404 status behaviour

Question

When you create a new webapplication, the FileNotFoundPage property is empty. When we do a request to a non existing page SharePoint gives a default 404 status on the page that is not found. The url of the page you are searching stays in addres bar. This is correct behaviour. We now set the FileNotFoundPage property with the sps404.html page that default exists in the layouts folder. SharePoint now redirects to this file that does a redirect itself to "/_layouts/spsredirect.aspx" when you trace this path you now get a 404 statuc on the page "/_layouts/spsredirect.aspx" and the address of the page you typed in also changes to "/_layouts/spsredirect.aspx"

Why this behavior?

What is the use of the sps404.html file?

What is the use of the "/_layouts/spsredirect.aspx" file

Answer 1

The /_layouts/spsredirect.aspx page was created in MOSS2007 to handle upgrading pages of what was known as bucketwebs in SPS2003. It'll take the oldUrl query string and see if it matches the url of a bucketweb, if that's the case it'll try to find the url of the corresponding upgraded site and if it finds it redirect the user to it.

If you didn't create your 2007 farm by upgrading a SPS2003 farm then you shouldn't use sps404.html and thereby spsredirect.aspx.

But if you want to have a custom aspx page as 404 page, then using a html page similar to sps404.html might be a good solution.