Strengthen the Default Ruleset
An XCCDF Group
Description
The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in the configuration filesiptables and ip6tables in the directory
/etc/sysconfig. Many of the lines in these files are similar
to the command line arguments that would be provided to the programs
/sbin/iptables or /sbin/ip6tables - but some are quite
different.
The following recommendations describe how to strengthen the default ruleset configuration file. An alternative to editing this configuration file is to create a shell script that makes calls to the iptables program to load in rules, and then invokes service iptables save to write those loaded rules to
/etc/sysconfig/iptables.
The following alterations can be made directly to
/etc/sysconfig/iptables and /etc/sysconfig/ip6tables.
Instructions apply to both unless otherwise noted. Language and address
conventions for regular iptables are used throughout this section;
configuration for ip6tables will be either analogous or explicitly
covered.
warning alert: Warning
The program
system-config-securitylevel
allows additional services to penetrate the default firewall rules
and automatically adjusts /etc/sysconfig/iptables. This program
is only useful if the default ruleset meets your security
requirements. Otherwise, this program should not be used to make
changes to the firewall configuration because it re-writes the
saved configuration file.- ID
- xccdf_org.ssgproject.content_group_iptables_ruleset_modifications
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