On their shields-up testing, they have a portion called "unsolicited packets" which they define as
What "questionable" systems counterprobe? Wtf is he talking about? I mean, I've never heard of an IDS/IPS doing that....
Unsolicited Packets: PASSED — No Internet packets of any sort were received from your system as a side-effect of our attempts to elicit some response from any of the ports listed above. Some questionable personal security systems expose their users by attempting to "counter-probe the prober", thus revealing themselves. But your system remained wisely silent. (Except for the fact that not all of its ports are completely stealthed as shown below.)
What "questionable" systems counterprobe? Wtf is he talking about? I mean, I've never heard of an IDS/IPS doing that....