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Locking Down Your Firewall
Scan your firewall
Portscan from the Outside:
From a machine outside your network, scan your firewall.
# nmap -sS -O 172.24.24.61
Starting nmap 3.81 ( http://www.insecure.org/nmap/ ) at 2005-04-03 20:33 CDT
Warning: OS detection will be MUCH less reliable because
we did not find at least 1 open and1 closed TCP port
Interesting ports on firewall (22.214.171.124):
(The 1662 ports scanned but not shown below are in state: filtered)
PORT STATE SERVICE
113/tcp closed auth
Too many fingerprints match this host to give specific OS details
Nmap finished: 1 IP address (1 host up) scanned in 31.835 seconds
Only a closed auth service is even visible. However, some may still want to
shut off even ICMP/ping type packets.
You may also want to do Destination Network Address Translation (DNAT) or port forwarding.
To do either of these, we need to edit our firewall script /etc/firewall.rules file