That seems to be a problem with your DHCP server then.
No, the DHCP server on the other side (local to the CentOS server) is currently serving an entire domain without issue. The CentOS was also a DHCP client until I made it static during this tutorial - after which it can still see everything fine, even browse the internet. Or are you referring to some DHCP mechanism the CentOS host is supposed to be providing these guests?
I can give the guests static IP addresses on the host's subnet and they can ping any machine on said subnet, even my 2003 Server domain controller (which is also our only DNS.) It seems I can do nothing more than ping those machines, however. It is as if a firewall on this host is filtering everything the guests try to pass through except ICMP, or the host bridge function is misconfigured here.