Q. How do I display / list all rules in the selected chain? How do I find out which rules are active? What is blocked and opened with my firewall?
A. To List all rules in the selected chain use the -L option. If no chain is selected, all chains are listed. As every other iptables command, it applies to the specified table. The -n option help to print IP addresses and port numbers in numeric format.
To check the status of your firewall and all rules, enter:
# iptables -L -n
OR
$ sudo iptables -L -n
Output:
Chain INPUT (policy ACCEPT) target prot opt source destination droplist all -- 0.0.0.0/0 0.0.0.0/0 droplist all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 66.228.118.0/23 0.0.0.0/0 DROP all -- 213.240.4.233 0.0.0.0/0 DROP all -- 75.126.132.23 0.0.0.0/0 DROP all -- 80.58.205.35 0.0.0.0/0 ..... ... ..... DROP all -- 91.200.56.0/22 0.0.0.0/0 LOG all -- 91.200.72.0/22 0.0.0.0/0 LOG flags 0 level 4 prefix `DROP List Block' DROP all -- 91.200.72.0/22 0.0.0.0/0
The –line-numbers option adds line numbers to the beginning of each rule, corresponding to that rule’s position in the chain. The -v option makes the list command show the interface name, the rule options (if any), and the TOS masks. The packet and byte counters are also listed, with the suffix K, M or G for 1000, 1,000,000 and 1,000,000,000 multipliers respectively (but see the -x flag to change this).
# iptables -L -v -n --line-numbers
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Great!! Thank you for the command this was really usefull!
-A FWR -p tcp -m tcp –dport 80 -j ACCEPT
I can someone tell me what the FWR stands for and/or mean?
Thanks.
FWR : FireWall Rule, it meens you have to precise the rule you want to setup : INPUT, for ingoing ports, or OUTPUT, for outgoing ports.
iptables -t nat -A POSTROUTING -i eth0 -j MASQUERADE
PLs can u tell me what the “-t” stands for?
The -t option specifies the packet matching table which the command should operate on.
This is great.
I just installed an app where I need to figure out how to change input_ports so that I connect to the app on a NAT-d server.
All this seems very confusing.
hi how can i add to the firewall and ip adress like that one ACCEPT 66.228.118.0/23
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all — 66.228.118.0/23 0.0.0.0/0
Thanks