STIGQter STIGQter: STIG Summary: Red Hat Enterprise Linux 9 Security Technical Implementation Guide Version: 2 Release: 9 Benchmark Date: 01 Jul 2026:

RHEL 9 must use reverse path filtering on all IPv4 interfaces.

DISA Rule

SV-257962r1155733_rule

Vulnerability Number

V-257962

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-09-253035

Severity

CAT II

CCI(s)

Weight

10

Fix Recommendation

Configure RHEL 9 to use reverse path filtering on all IPv4 interfaces.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/99-ipv4_rp_filter.conf

Add the following line to the file:
net.ipv4.conf.all.rp_filter = 1

Reload settings from all system configuration files with the following command:

$ sudo sysctl --system

Check Contents

Verify RHEL 9 uses reverse path filtering on all IPv4 interfaces.

Check the value of the "rp_filter" variable with the following command:

$ sudo sysctl net.ipv4.conf.all.rp_filter
net.ipv4.conf.all.rp_filter = 1

If "net.ipv4.conf.all.rp_filter" is not set to "1" or is missing, this is a finding.

Vulnerability Number

V-257962

Documentable

False

Rule Version

RHEL-09-253035

Severity Override Guidance

Verify RHEL 9 uses reverse path filtering on all IPv4 interfaces.

Check the value of the "rp_filter" variable with the following command:

$ sudo sysctl net.ipv4.conf.all.rp_filter
net.ipv4.conf.all.rp_filter = 1

If "net.ipv4.conf.all.rp_filter" is not set to "1" or is missing, this is a finding.

Check Content Reference

M

Target Key

5551