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V-12023

CAT II (Medium)

IP forwarding for IPv4 must not be enabled, unless the system is a router.

Rule ID

SV-46114r1_rule

STIG

SUSE Linux Enterprise Server v11 for System z Security Technical Implementation Guide

Version

V1R12

CCIs

CCI-000366

Discussion

If the system is configured for IP forwarding and is not a designated router, it could be used to bypass network security by providing a path for communication not filtered by network devices.

Check Content

Check if the system is configured for IPv4 forwarding. If the system is a VM host and acts as a router solely for the benefits of its client systems, then this rule is not applicable.

Procedure:
# cat /proc/sys/net/ipv4/ip_forward

If the value is set to "1", IPv4 forwarding is enabled this is a finding.

Fix Text

Edit "/etc/sysctl.conf" and set net.ipv4.ip_forward to "0". Restart the system or run "sysctl -p" to make the change take effect.