3.4.3.3.3 Ensure ip6tables outbound and established connections are configured

Information

Configure the firewall rules for new outbound, and established IPv6 connections.

Note:

- Changing firewall settings while connected over network can result in being locked out of the system
- Remediation will only affect the active system firewall, be sure to configure the default policy in your firewall management to apply on boot as well

If rules are not in place for new outbound, and established connections all packets will be dropped by the default policy preventing network usage.

Solution

Configure iptables in accordance with site policy. The following commands will implement a policy to allow all outbound connections and all established connections:

# ip6tables -A OUTPUT -p tcp -m state --state NEW,ESTABLISHED -j ACCEPT
# ip6tables -A OUTPUT -p udp -m state --state NEW,ESTABLISHED -j ACCEPT
# ip6tables -A OUTPUT -p icmp -m state --state NEW,ESTABLISHED -j ACCEPT
# ip6tables -A INPUT -p tcp -m state --state ESTABLISHED -j ACCEPT
# ip6tables -A INPUT -p udp -m state --state ESTABLISHED -j ACCEPT
# ip6tables -A INPUT -p icmp -m state --state ESTABLISHED -j ACCEPT

See Also

https://workbench.cisecurity.org/benchmarks/13775

Item Details

Category: SECURITY ASSESSMENT AND AUTHORIZATION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CA-9, 800-53|SC-7, 800-53|SC-7(5), CSCv7|9.4

Plugin: Unix

Control ID: 0c53e918e1bc0b12e351703e17df1cc1b32e09d23b1263aded1c91cd5b06037b