ISC DHCP option for updating A RR ?

[vu pham]

I use ISC DHCP (3.0.5) to make ddns update to the dns server ( bind 
9.3.4 ). I notice that for dhcp-client PCs that are not in a Windows 
domain , the dhcp server will do the update for the A RR and the PTR RR, 
and for dhcp-client PCs that are in a domain, the dhcp server will only 
do the update for PTR RR.

Ethereal shows in both cases, the dhcp clients request the server *not* 
to update the A RR ( in DHCP REQUEST option 81 FQDN bit 7) and the dhcp 
server ACKs them differently.

For non-domain PCs, the server sets the overidden bit to 1 ( in DHCK 
ACK, option 81 FQDN  bit 6), which means it will update the A RR even 
when the client does not want the server to do that. And for domain PCs, 
the servers set that bit to 0.

Do we have any option in dhcpd.conf that can force the server to always 
update the A RR ?

Thanks,

Vu