The Red Hat Enterprise Linux operating system must use a reverse-path filter for IPv4 network traffic when possible on all interfaces.
An XCCDF Rule
Description
<VulnDiscussion>Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems that are routers for complicated networks, but is helpful for end hosts and routers serving small networks.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-204610r880800_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
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.conf.all.rp_filter = 1
Issue the following command to make the changes take effect: