iptablesrocks.org - an iptables guide & tutorial
The iptablesrocks.org iptables firewall setup guide
Testing your new firewall:

With you firewall now up and running, it's time to run a few simple tests on it to make sure it's doing it's job.

From a remote server, try the following:

1. SSH to your server. A successful connection will be logged in the firewall logs at /var/log/firewall. This will ensure that the ACCEPT logging functions are working correctly.

2. Run the "nmap" utility against your server (nmap 1.2.3.4, where 1.2.3.4 is your server's IP). The default namp attempt will probably fail. This is good. You can add other flags to the nmap probe to further test the server. While your firewall won't be albo to block ALL portscans, it should block many and make the others a bit more time consuming and troublesome. A portion nmap probe's activities should be logged in the /var/log/firewall logfile. The log entries will confirm that the server's DROP logging functions are working correctly.

3. Try to ping your server. This should fail, since all ping requests are being dropped by the firewall.

4. FTP to your server and test for full FTP functionality. If you can't get directly listings, you will need to add the "ip_conntrack_ftp" module with the command "insmod ip_conntrack_ftp".

OK, assuming all your tests went smoothly your firewall should be in good shape. In the next step, we'll install the "Iptables Log Analyzer" package which will allow you to view your log entries in a nice web based environment.

Proceed to the next step

 

 
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Site last modified: October 25, 2005 09:20:01
 
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