What does it mean when non-existant urls bring up my page?

[artdog]

Looking through my logs found pages to my site that don't exist returning a 200 code and loading up the home page!

example
www.mysite.com/?N=D
www.mysite.com/?N=A

The /?N=D doesn't exist on my server yet loads up my home page, is someone messing with my site? Site is a popular type in with only one page that really delivers the info and converts beyond my expectations.

Should I be concerned?

[digitalghost]

Do you have a 404 handler in place?

[encyclo]

Has the page ever been indexed when there was no default index page? The above URLs are for the resorting options on an auto-generated directory listing in Apache.

You will probably find that your page serves up a 200 OK to anything after a question mark. Try:

www.example.com/?foobar

If the URLs are causing a problem, then try using mod_rewrite to 301 redirect them to the correct URL.

[artdog]

Site was parked for a few months at registrar, it's doing so well wish I got content on it sooner.

/?foobar works too

Will do a 301 but don't know how to do the "404 handler"

Thanks a bunch for the help.

[artdog]

Traffic has plumeted over the last two days even though ranking is unchanged, or at least AWSTATS and Webilizer reporting shows almost no traffic.

Sales are coming in normally though.

Another odd thing is adsense not working on page, just shows a public service anouncement, could this be a clue to something?

[jake66]

i've been trying to figure this out myself for ages.
how could you set up a 404 on these types of url's?