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

RHEL 9 must prevent IPv6 Internet Control Message Protocol (ICMP) redirect messages from being accepted.

DISA Rule

SV-257976r1155769_rule

Vulnerability Number

V-257976

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-09-254035

Severity

CAT II

CCI(s)

CCI-000366 - Implement the security configuration settings.

Weight

Fix Recommendation

Configure RHEL 9 to prevent IPv6 ICMP redirect messages from being accepted.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/ipv6_accept_redirects.conf

Add the following line to the file:
net.ipv6.conf.default.accept_redirects = 0

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

$ sudo sysctl --system

Check Contents

Verify RHEL 9 to prevent IPv6 ICMP redirect messages.

Note: If IPv6 is disabled on the system, this requirement is Not Applicable.

Check the value of the "net.ipv6.conf.default.accept_redirects" variables with the following command:

$ sudo sysctl net.ipv6.conf.default.accept_redirects
net.ipv6.conf.default.accept_redirects = 0

If "net.ipv6.conf.default.accept_redirects" is not set to "0" or is missing, this is a finding.

Vulnerability Number

V-257976

Documentable

False

Rule Version

RHEL-09-254035

Severity Override Guidance

Check Content Reference

Target Key

5551