Services not starting due to DHCP ?

I think that the delayed response from the dhcp server is causing my network related services to timeout/not find addresses (ie nfs mounts, nis, ntp, etc) When it boots up it complains that it cant find the servers .. but once the machine is up, if I start any of the services that failed during boot up, they all seem to work fine. Has anyone had something similar to this ? does anyone know if I can increase the timeout before it gives up on dhcp and continues to boot ? Btw this is sles9 and happens on every machine I have .. I would almost suggest looking at the dhcp server .. but since we are a large corp. this is not an option. Any help would be great.. Thanks, rod