The DHCP client must not send dynamic DNS updates.

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

Associated with: CCI-000366

SV-45988r2_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 "dhcp-client" package is not installed, this is not applicable. Verify the DHCP client is configured to not send dynamic DNS updates. Procedure: # rpm –q dhcp-client If DHCP client is found then issue following command to determine if the DHCP client sends dynamic DNS updates: # grep do-forward-updates /etc/dhclient.conf If the DHCP client is installed and the configuration file is not present, or contains do-forward-updates = “true”, then 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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