Ip6tables is used to set up, maintain, and inspect the tables of IPv6 packet filter rules in the Linux kernel. The following configuration is tested on:
- CentOS Linux 5.x
- Red Hat Enterprise Linux 5.x
- Fedora Linux 10 and 11.
# ip6tables -nL --line-numbers
If no rules appear, activate IPv6 firewall and ensure that it starts at boot by typing the following command:
# chkconfig ip6tables on
/etc/sysconfig/ip6tables
Edit /etc/sysconfig/ip6tables, enter:# vi /etc/sysconfig/ip6tables
You will see default rules as follows:
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:RH-Firewall-1-INPUT - [0:0]
-A INPUT -j RH-Firewall-1-INPUT
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmpv6 -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 5353 -d ff02::fb -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 32768:61000 -j ACCEPT
-A RH-Firewall-1-INPUT -p tcp -m tcp --dport 32768:61000 ! --syn -j ACCEPT
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp6-adm-prohibited
COMMIT
To open port 80 (Http server) add the following before COMMIT line:
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 80 -j ACCEPT
To open port 53 (DNS Server) add the following before COMMIT line:
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 53 -j ACCEPT
-A RH-Firewall-1-INPUT -m udp -p tcp --dport 53 -j ACCEPT
To open port 443 (Https server) add the following before COMMIT line:
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 443 -j ACCEPT
To open port 25 (smtp server) add the following before COMMIT line:
-A RH-Firewall-1-INPUT -m tcp -p tcp --dport 25 -j ACCEPT
To log before dropping all packets that are not explicitly accepted by previous rules, change the final lines from:
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp6-adm-prohibited
COMMIT
To:
-A RH-Firewall-1-INPUT -j LOG
-A RH-Firewall-1-INPUT -j DROP
COMMIT
Save and close the file. Restart ip6tables firewall:
# service ip6tables restart
# ip6tables -vnL --line-numbers
Sample Outputs:
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 42237 3243K RH-Firewall-1-INPUT all * * ::/0 ::/0
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 0 0 RH-Firewall-1-INPUT all * * ::/0 ::/0
Chain OUTPUT (policy ACCEPT 12557 packets, 2042K bytes)
num pkts bytes target prot opt in out source destination
Chain RH-Firewall-1-INPUT (2 references)
num pkts bytes target prot opt in out source destination
1 6 656 ACCEPT all lo * ::/0 ::/0
2 37519 2730K ACCEPT icmpv6 * * ::/0 ::/0
3 0 0 ACCEPT esp * * ::/0 ::/0
4 0 0 ACCEPT ah * * ::/0 ::/0
5 413 48385 ACCEPT udp * * ::/0 ff02::fb/128 udp dpt:5353
6 0 0 ACCEPT udp * * ::/0 ::/0 udp dpt:631
7 0 0 ACCEPT tcp * * ::/0 ::/0 tcp dpt:631
8 173 79521 ACCEPT udp * * ::/0 ::/0 udp dpts:32768:61000
9 0 0 ACCEPT tcp * * ::/0 ::/0 tcp dpts:32768:61000 flags:!0x16/0x02
10 0 0 ACCEPT tcp * * ::/0 ::/0 tcp dpt:22
11 0 0 ACCEPT tcp * * ::/0 ::/0 tcp dpt:80
12 0 0 ACCEPT tcp * * ::/0 ::/0 tcp dpt:53
13 4108 380K ACCEPT udp * * ::/0 ::/0 udp dpt:53
14 18 4196 REJECT all * * ::/0 ::/0 reject-with icmp6-adm-prohibited
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