DHCP works by indexing ethernet hardware addresses against their
respective IP configurations. A computer that's using DHCP sends out a
request to the network to get configured, which is received by the DHCP
server, which then sends appropriate return messages to configure the DHCP
client.
Personally, I don't use any boot protocol whatsoever to get my
computer up and running - I just have all my IP information (IP number,
default gateway, netmask, etc.) hard-coded. It makes bootup a little
quicker on those rare occassions when I reboot.
The other thing is that RedHat's default DHCP setup does some
funky stuff. First of all, it overwrites /etc/resolv.conf, which you
probably don't want, because it gets rid of your extra DNS servers, gets
rid of any search domains you've configured, and so on. The other thing is
that if you have a vanity domain name (the existence of which has already
been touched upon), it'll set your hostname to the netxx-xx thing even
though that's no longer your hostname.
Fixing both these problems requires editing one of the DHCP
configuration scripts; I think the file is
/etc/sysconfig/network/ifdhcp-done (if not, it's in a similar directory).
For the first problem, comment out the lines that copy over the new
resolv.conf that you don't want to be copied over; for the second, put the
following lines at the end of the script:
hostname <hostname>
export HOSTNAME <hostname>
(<hostname> being whatever your vanity domain name is.)
Matt