7.2. IP6Tables

The introduction of the next-generation Internet Protocol, called IPv6, expands beyond the 32-bit address limit of IPv4 (or IP). IPv6 supports 128-bit addresses and, as such, carrier networks that are IPv6 aware are able to address a larger number of routable addresses than IPv4.

Red Hat Linux supports IPv6 firewall rules using the Netfilter 6 subsystem and the IP6Tables command. The first step in using IP6Tables is to start the IP6Tables service. This can be done with the command:

service ip6tables start


The IPChains and IPTables services must be turned off to use the IP6Tables service exclusively:

service ipchains stop
chkconfig ipchains off
service iptables stop
chkconfig iptables off

To make IP6Tables start by default whenever the system is booted, change the runlevel status on the service using chkconfig.

chkconfig --level 345 ip6tables on

The syntax is identical to IPTables in every aspect except that IP6Tables supports 128-bit addresses. For example, SSH connections on a IPv6-aware network server can be enabled with the following rule:

ip6tables -A INPUT -i eth0 -p tcp -s 3ffe:ffff:100::1/128 --dport 22 -j ACCEPT

For more information about IPv6 networking, refer to the IPv6 Information Page at http://www.ipv6.org.