I just don't understand Firewalls

I confess. I’m a Firewall Idiot. I just don’t understand them. I mean, I know the general idea, but as for “settings”, I’m completely lost. This is not just with Comodo. I’ve used other Firewalls and felt the same dismay–but as for my current problem:

I don’t know how I did it, but I seem to have firewalled my internet connection, so now I can’t get my (other, XP computer) on the net.

Where do I go in settings to fix this?

(Another thing. When Comodo recommends I “submit a suspicious file to Comodo for analysis,” how is that done? Seems like there’s an obvious need for an obvious button there.)

Welcome to the forum Phrixos2, lets start with some of the obvious things you may have inadvertantly done which could stop your connection. Could you also let us know how you connect, e.g. through a router or connected directly to a modem.

From the main interface go to Firewall->Advanced->Firewall Behaviour Settings->Where is the slider set to?
If you have clicked “Stop all activities” by accident it will be at Block All.

Now lets have a look in “Network Security Policy” Firewall->Advanced->Network Security Policy(application rules)->See if you have any entries in there which just have the rule Block and Log IP any from IP any to IP any where protocol is any. Look out for entries System, svchost.exe or Windows Updater applications.
Also have a look in the Global rules for any entries which may be relevant.

What does your logs say? Firewall->Common tasks->View Firewall Events, when you try and connect


Hello, and thanks for replying.

I am on a router.
My security alert level slider is set to Safe Mode.
“Block All” Mode is not checked. (I don’t see any " Stop All Activities" button, anywhere.)

Under Application Rules there is the following Entry:

“Comodo Internet Security (Outgoing Only)”
under it (and next to a green check) is "Allow all outgoing requests (but this is grayed out).
under that (and next to a red X) is "Block and Log all unmatching requests (but this too is grayed out).

(I gather that a red X refers to blocks: there are no other red x’s in Application Rules

In Global Rules, things are very different:
"Block ICMP Out from IP Any to IP Any Where ICMP Message is

Sorry. Message was sent prematurely.

In Global Rules, things are very different:
"Block ICMP Out from IP Any to IP Any Where ICMP Message is PROTOCOL UNREACHABLE.
"Block ICMP … message is 17.0
"Block ICMP … message is 15.0
"Block ICMP … message is 13.0
“Block ICMP … message is ECHO REQUEST”

“Firewall Events” is empty
(Don’t see any “Help” button either.)


I just noticed that my Windows Firewall is active alongside.

Should this be disabled when Comodo is working?

Windows firewall should be disabled if you are using Comodo Internet Securtiy.

Have you tried doing a repair of your connection? Some info: http://www.microsoft.com/windowsxp/using/networking/maintain/repair.mspx

Some more possible helpful info, http://www.microsoft.com/windowsxp/using/networking/maintain/troubleshoot.mspx

Your computer should get it`s IP address from the router using DHCP. Where you able to connect at some point when you had CIS installed?
Make sure there is nothing in Firewall/Common tasks/My Blocked Network Zones->If there is remove it.