dynamic dns dhcp dealing with invalid host names

[Tim Alberts]

I'm running dhcpd with dynamic DNS for the network and I regularly get 
errors such as:

Jan  4 13:04:14 msi2 named[18496]: zone example.com/IN: IMac\0321.example.com
/A: bad owner name (check-names)
Jan  4 13:04:14 msi2 dhcpd: Unable to add forward map from IMac 1.example.com
 to 192.168.0.185: timed out


The fix is to change the client hostname to remove the space character.  
However, clients refuse to follow the naming conventions and keep 
putting space characters in the host name.

Can I configure DHCP/DNS to accept this or better yet, refuse to get 
them an address if the name is invalid?