<filter name='allow-dhcp-server' chain='ipv4'>

    <!-- accept outgoing DHCP requests
         note, this rule must be evaluated before general MAC broadcast
         traffic is discarded since DHCP requests use MAC broadcast -->
    <rule action='accept' direction='out' priority='100'>
        <ip srcipaddr='0.0.0.0'
            dstipaddr='255.255.255.255'
            protocol='udp'
            srcportstart='68'
            dstportstart='67' />
    </rule>

    <!-- accept incoming DHCP responses from a specific DHCP server
         parameter DHPCSERVER needs to be passed from where this filter is
         referenced -->
    <rule action='accept' direction='in' priority='100' >
        <ip srcipaddr='$DHCPSERVER'
            protocol='udp'
            srcportstart='67'
            dstportstart='68'/>
    </rule>

</filter>
