SLEM 5 must not be performing Internet Protocol version 6 (IPv6) packet forwarding by default unless the system is a router.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-261326SRG-OS-000480-GPOS-00227SLEM-05-254035SV-261326r996448_rule2024-06-041
Description
Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network.
ℹ️ Check
Verify SLEM 5 is not performing IPv6 packet forwarding by default, unless the system is a router with the following command: > sudo sysctl net.ipv6.conf.default.forwarding net.ipv6.conf.default.forwarding = 0 If the network parameter "ipv6.conf.default.forwarding" is not equal to "0", or nothing is returned, this is a finding.
✔️ Fix
Configure SLEM 5 to not performing IPv6 packet forwarding by default by running the following command as an administrator: > sudo sysctl -w net.ipv6.conf.default.forwarding=0 If "0" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf": > sudo sh -c 'echo "net.ipv6.conf.default.forwarding=0" >> /etc/sysctl.d/99-stig.conf' > sudo sysctl --system