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I'm using CentOS and when type the command:

iptables -L -v

The output is as follows:

Chain INPUT (policy ACCEPT 19614 packets, 2312K bytes) pkts bytes target prot opt in out source destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target
prot opt in out source destination

Chain OUTPUT (policy ACCEPT 13881 packets, 32M bytes) pkts bytes target prot opt in out source destination

What does this mean?

I'm able to connect using SSH. Where can I see that rule?

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2 Answers 2

up vote 5 down vote accepted

Empty tables mean you have no rules. Having no rules means the table "policy" controls what happens to each packet traversing that table. The policy ACCEPT on each table means that all packets are allowed through each table. Thus, you have no firewall active.

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You don't have any rules set up. Take a look at the following iptables tutorial on how to add your rules:


You can add your SSH rule like so, which will allow all SSH through Port 22:

iptables -A INPUT -p tcp --dport 22 -j ACCEPT

You may get a better response if you post on the Unix and Linux board.

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Thanks, maybe I was not clear. I'm surprising that how can I connect using SSH if I don't have any rule yet. What means empty table? Allow all connections or what? –  Memochipan Jun 15 '12 at 3:48
@Memochipan Note how the listing contains the policy: "policy ACCEPT" -> that's the default rule, which in this case, is accept all traffic. Your iptables is effectively disabled as a firewall without any rules to block traffic. –  Darth Android Jun 15 '12 at 15:27

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