GRC ShieldsUp Scan...

Hi, strange one here…
Done a “allservice ports” scan on the shieldsup website and all was fine, true stealth.
Then i done a “user Specific” port scan which i chose ports 100 & 120 and it failed on:
Unsolicited Packets: RECEIVED (FAILED) — Your system’s personal security countermeasures unwisely attempted to probe us in response to our probes.

I then chose “allservice ports” scan again and it failed like the above !??!

Comodo did not prompt for any user action during any of the scans so i cant figure out why it is now failing the stealth tests.
Any ideas ?

Just a guess, but perhaps CPF is ‘adaptive’ and changed its behaviour between the first (pass test) and subsequent ones?

I think ZoneAlarm does (or used to do) this on port 113 (Ident). For a while at least, it was the only one that did it properly in that respect, but I assume everyone else has caught up on that now.

I might be completely wrong though!


You can try to run the same test with firewall disabled, i guess you’ll be having the same results.

CIS Firewall does not send active packets back to the “attacker”, if you allow traffic to port 100 and you system has no listening port for it it will default respond with a TCP Reset packet to let the other side know there is nothing there…

Do you have a modem/router in between your internet connection and your pc(s) ?