autodiscover/autodiscover.xml

[leveni]

Through our webstats we have noticed recently that we are getting an increasing amount of 404 errors to the page www.domainname.co.uk/autodiscover/autodiscover.xml. Ive managed to find out what the autodiscover.xml is but what I havnt been able to work out is where the hits are coming from.

We dont use this Exchange 2007 autodiscover feature so the xml file doesnt exist on our webserver but because were getting hundreds of hits for the file per month we would like an idea of what is causing the hits.

Is it mobile devices? Is it bots phising for the file or some other explanation.

Any info would of great help.

[enigma1]

Hits may come up from all over the place. Here is one method:
example.com sets up page test.html and within the page content, they add your domain/autodiscover/autodiscover.xml via an image tag or some other resource which can be hidden btw using some trivial css. You may think it helps SEO? It doesn't.
Now as visitors access the test.html page, their browsers will attempt to retrieve the autodiscover.xml file from your server. This can be extended with search engines as they index pages like the test.html, then others who browse the SE cache of test.html and even other sites who perhaps pull-in content from example.com for display. Now the more popular the test.html pages are, the more connections they can waste from your server, so you see the side-effects that can happen.
So instead of 404s perhaps you could redirect these requests to rogue servers and spam sites unloading the garbage to them. 301s consume a bit less bandwidth anyways that 404 content.