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DoS Attack Filter

Aymeric Levaux

Joined: Apr 01, 2004
Posts: 11
I'm looking for a J2EE filter to prevent DoS attack. Does any body knows such filter ?
Jeanne Boyarsky
author & internet detective

Joined: May 26, 2003
Posts: 33124

Technically speaking you can't prevent a DoS attack; only minimize its impact. In particular, the resources of serving the request and getting to the filter are still used. In some cases, this may be enough to get the server to 100% capacity.

The best you can do is cache the IP addresses that make requests in the filter and not process the request if there are X number from a certain IP within a predetermined interval. Note that proxy servers make it look like many users are coming from the same IP. So it is legitimate to have concurrent requests.

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I agree. Here's the link:
subject: DoS Attack Filter
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