UCF STIG Viewer Logo

The Red Hat Enterprise Linux operating system must not be performing packet forwarding unless the system is a router.


Overview

Finding ID Version Rule ID IA Controls Severity
V-72309 RHEL-07-040740 SV-86933r2_rule Medium
Description
Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network.
STIG Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide 2018-11-28

Details

Check Text ( C-72543r2_chk )
Verify the system is not performing packet forwarding, unless the system is a router.

# grep net.ipv4.ip_forward /etc/sysctl.conf /etc/sysctl.d/*

net.ipv4.ip_forward = 0

If "net.ipv4.ip_forward" is not configured in the /etc/sysctl.conf file or in the /etc/sysctl.d/ directory, is commented out, or does not have a value of "0", this is a finding.

Check that the operating system does not implement IP forwarding using the following command:

# /sbin/sysctl -a | grep net.ipv4.ip_forward
net.ipv4.ip_forward = 0

If IP forwarding value is "1" and the system is hosting any application, database, or web servers, this is a finding.
Fix Text (F-78663r2_fix)
Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a configuration file in the /etc/sysctl.d/ directory (or modify the line to have the required value):

net.ipv4.ip_forward = 0

Issue the following command to make the changes take effect:

# sysctl --system