The DHCP client must not send dynamic DNS updates.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-000366

SV-63409r1_rule The DHCP client must not send dynamic DNS updates.

Vulnerability discussion

Dynamic DNS updates transmit unencrypted information about a system including its name and address and should not be used unless needed.

Check content

If the "dhclient" package is not installed, this is not applicable. Verify the DHCP client is configured to not send dynamic DNS updates. Procedure: # grep do-forward-updates /etc/dhclient.conf If the file is not present, does not contain this configuration, or has the setting set to "true", this is a finding.

Fix text

Edit or add the "/etc/dhclient.conf" file and add or edit the "do-forward-updates" setting to false. Procedure: # echo "do-forward-updates false;" >> /etc/dhclient.conf

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