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

RHEL 9 must not forward IPv6 source-routed packets by default.

DISA Rule

SV-257977r1155772_rule

Vulnerability Number

V-257977

Group Title

SRG-OS-000480-GPOS-00227

Rule Version

RHEL-09-254040

Severity

CAT II

CCI(s)

CCI-000366 - Implement the security configuration settings.

Weight

Fix Recommendation

Configure RHEL 9 to not accept IPv6 source-routed packets by default.

Create a configuration file if it does not already exist:

$ sudo vi /etc/sysctl.d/ipv6_accept_source_route.conf

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

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

$ sudo sysctl --system

Check Contents

Verify RHEL 9 does not accept IPv6 source-routed packets by default.

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

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

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

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

Vulnerability Number

V-257977

Documentable

False

Rule Version

RHEL-09-254040

Severity Override Guidance

Check Content Reference

Target Key

5551