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RHEL-10-800130 RHEL 10 must use reverse path filtering on all Internet Protocol version 4 (IPv4) interfaces.

DISA STIG library V1R3
All changes in this version
first version loaded CAT II

Maps to SC-5 via CCI-002385, CCI-001100

Title

RHEL 10 must use reverse path filtering on all Internet Protocol version 4 (IPv4) interfaces.

Control

Verify RHEL 10 uses reverse path filtering on all IPv4 interfaces. Check the value of the "net.ipv4.conf.all.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.

Discussion

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. Satisfies: SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00076

Related controls

CCI-001100, CCI-002385

Fix

Configure RHEL 10 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