AQTRONIX WebKnight is an application firewall for IIS and other web servers and is released under the GNU General Public License.
More particularly it is an ISAPI filter that secures your web server by blocking certain requests.
If an alert is triggered WebKnight will take over and protect the web server.
It does this by scanning all requests and processing them based on filter rules, set by the administrator.
These rules are not based on a database of attack signatures that require regular updates.
Instead WebKnight uses security filters as buffer overflow, SQL injection, directory traversal, character encoding and other attacks.
This way WebKnight can protect your server against all known and unknown attacks.
Because WebKnight is an ISAPI filter it has the advantage of working closely with the web server, this way it can do more than other firewalls and intrusion detection systems, like scanning encrypted traffic.
More Details:AQTRONIX WebKnight