Here is a comparison of a port scan of my box, with the firewall turned off on the first one and then turned on on the second one. Note: my system is a very secure system, even with the firewall off. I have disabled all netbios and turned off all un-necessary services.
Firewall off:
GRC Port Authority Report created on UTC: 2003-12-14 at 22:25:23
Results from scan of ports: 0-1055
1 Ports Open
1048 Ports Closed
7 Ports Stealth
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1056 Ports Tested
The port found to be OPEN was: 1025
Ports found to be STEALTH were: 135, 136, 137, 138, 139, 445,
593
Other than what is listed above, all ports are CLOSED.
TruStealth: FAILED - NOT all tested ports were STEALTH,
- NO unsolicited packets were received,
- NO Ping reply (ICMP Echo) was received.
And this with the Firewall on:
GRC Port Authority Report created on UTC: 2003-12-14 at 22:29:40
Results from scan of ports: 0-1055
0 Ports Open
0 Ports Closed
1056 Ports Stealth
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1056 Ports Tested
ALL PORTS tested were found to be: STEALTH.
TruStealth: PASSED - ALL tested ports were STEALTH,
- NO unsolicited packets were received,
- NO Ping reply (ICMP Echo) was received.