CentOS - Jun 2012 - dhclient-eth0.conf question

I have the line:
request tftp-server-name;
in my centos 6.2 dhclient-eth0.conf file

If the tftp-server-name is given by the DHCP server everything is fine.
however, if it is NOT given the client seems to error out and does not 
get an address and is not on the network.
I then take the line out and do service network restart and it works 
just fine.

How can I make this an optional thing? If the server can provide it fine 
if not thats fine and just keep going?
How do I do that?

Thanks,

Jerry