dang, thats redhat
search for eth0 (or wait for greg) there should be a text file that describes how the network card should be booted with parameters. Sounds like something isnt getting saved. Can you do a tcpdump -n -i eth0 in a command line while in another window renew the dhcp lease. The tcpdump will see what packets are being requested where and may have a clue
Any opinions expressed by me are mine alone, posted from my home computer, on my own time as a free American and do not reflect the opinions of any person or company that I have had professional relations with in the past 55 years. meep