How do I know my firewall is working?
 

I have a linksys router. How do I know my firewall is working? Is there a way to check?

I use http://grc.com and follow the links for the Shields Up test. There is a link there to test the first thousand or so ports.

Unless you have a good reason to have a server runing on your machine with an open port, all ports should be either closed or stealth mode.

Well, one thing you could do is start up a webserver on one of your computers inside and specifically not forward that port to the machine.

Then go a friend's house, launch IE, and try to navigate to your IP, see if you can bring up the webserver. If you can, something ain't right.

Feel free to substitute whatever protocol you like best for a webserver [SSH server, telnet, FTP, etc.]

I checked, and it's not working. By the way, I found some very interesting pictures on your pc. :eek:




Kidding of course :D

Honestly, GRC's shield's up test is not the greatest. I've had it give me wildly inaccurate readings on my OpenBSD machine -- even different results between two back-to-back tests without changing anything.

If you really want to test, you can't beat NMap

Norton has a test that I use

http://security.symantec.com/ssc/

I dont know if it requires subscription to NAV, but give it a shot.

Norton's test dosent work in Mozilla.....

what's your IP...I'll scan your router for adequate firewall protection.

If you want to do it yourself get a port scanner and run it against your IP address from outside your network (i.e. everything behind your linksys).

I like GFI's LanGuard plus. Comprehensive and nice report type output.

A firewall is only one tool to use in protecting your network. Make sure that the nodes behind it are also not running any services that don't need to be running, and that you have mitigated vulnerabilities for the services which are. Also make sure you don't have vulnerabilities to the firewall itself. Those SOHO dealios from linksys or netgear have default passwords (did you change them?), and remote administration (did you turn it off?) capabilities.

-bear

i use nmap from an outside pc...i think there's a win version now.