Avoid bot crawling of filter urls

Hi,

we have the massive problem that bots go crazy about the filter urls. For example they exploit long “or” requests like this one:

/schuhe/groesse-13-2-or-25-or-29-or-34-35-or-36-38-or-37-or-40-or-430-or-45-46-or-46-47-or-475-or-80g-or-9-5-or-m-or-us-10-or-us-13-or-us-7-5-or-us-8-or-us-9-5/

This puts a lot of load on our server. We already disallowed “or” and other url parameters. But is there also another way to protect against this exploit. We have always deactivated all indexing in your plugin.

How do the bots get the urls. They pretty much like more to use the filter url structure then the core product-category pages or product pages. Does your plugin store a sitemap for the filter-urls somewhere? Any hints, ideas to solve this is appreciated.

Regards