AlmaLinux OS 9 must use reverse path filtering on all IP interfaces.
An XCCDF Rule
Description
Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface on which they were received. It must not be used on systems that are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
- ID
- SV-269255r1050137_rule
- Version
- ALMA-09-019820
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure AlmaLinux OS 9 to use reverse path filtering on all IP interfaces.
Create a numbered *.conf file in /etc/sysctl.d/ with the following content:
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1