Ports not stealthed [RESOLVED]

I am quite new to Comodo.
I tested this firewall with Shields-up (Shields UP!! — System Error) and it told me that all my ports (except port 0) where closed instead of stealthed.
I remember that with Zone Alarm all my ports where stealthed.
Did I forget some setting?


Do you connect to the internet through a router (or a modem/router)?

If so, the IP address that is being tested is the public IP address of your router, not the IP address currently assigned to your PC. This can be confirmed by comparing the IP address that ShieldsUp says it is testing to the IP address of your network card.

To discover the IP address of your PC click START - RUN, type “cmd” and press ENTER. This will open a DOS-style window. In this window, type “ipconfig /all” and press ENTER. This will display the current IP configuration of the PC.

In laymans terms, a router “sort of” has two network cards - one facing inwards to your LAN/PC and the other facing outwards towards your ISP. The inwards facing one will have a private address that is similar (on the same subnet) as the IP address of your PC.

If you want ShieldsUp to test the firewall on the PC, you will need to forward all of the ports in the range 0-1056 from your router to the PC you want to test.

What is port forwarding?

Assume the following;
Your PC has an address of
Your router has an external IP address of
Port 21 is used for FTP inbound requests

As you are set up at the moment, if someone on the internet probes port 21 on your public IP (your router) the firewall on the router responds according to it’s rule set. The firewall on the PC doesn’t even know anything is happening as the traffic is interacting with the router.

If, on the router, we forward port 21 from to, then any subsequent probes on port 21 received on (the router) are forwarded transparently to (your PC). Now, the firewall on the PC will have to deal with the incoming traffic, as the router is forwarding traffic on the designated port to the designated internal address.

To get ShieldsUp to test your PCs firewall (as opposed to your routers firewall), you will need to port forward ALL ports from 0 to 1056 (the port range tested by ShieldsUp).

Hope this helps,
Ewen :slight_smile:

The router!
I completely forgot it!
Yes you are right: the ports are not forwarded.
Thank you for the very detailed explanations.

No worries. I’ll mark this as closed and lock it. If you need it reopened, either PM me or one of the other mods.

Ewen :slight_smile: