pfSense

This is what was entered in the config on a fresh install of 2.1 not 2.1.1.
It seems to automatically enter the range into the config during the setup. This was done from the console and option #2 "Set interface(s) IP address" after a fresh install.

<dhcpdv6>
        <lan>
            <ramode>managed</ramode>
            <rapriority>low</rapriority>
            <rainterface/>
            <radomainsearchlist/>
            <range>
                <from>2001:470:xxxx:1::1000</from>
                <to>2001:470:xxxx:1::2000</to>
            </range>
            <prefixrange>
                <from/>
                <to/>
                <prefixlength>48</prefixlength>
            </prefixrange>
            <defaultleasetime/>
            <maxleasetime/>
            <netmask/>
            <domain/>
            <domainsearchlist/>
            <ddnsdomain/>
            <tftp/>
            <ldap/>
            <nextserver/>
            <filename/>
            <rootpath/>
            <dhcpv6leaseinlocaltime/>
            <numberoptions/>
        </lan>
    </dhcpdv6>