DHCP is the protocol for handing out IP addresses. First see if the dhcp daemon is running:
If that's running, see if it is logging anything:
sudo grep dhcpd /var/log/messages
If is ok, it should be logging when it gives out leases. Something like:
Nov 20 16:44:20 smallpond dhcpd: Wrote 18 leases to leases file.
Nov 20 16:44:20 smallpond dhcpd: DHCPREQUEST for 192.168.0.132 from 00:21:63:b5:df:57 (Maria) via p1p1
Nov 20 16:44:20 smallpond dhcpd: DHCPACK on 192.168.0.132 to 00:21:63:b5:df:57 (Maria) via p1p1
Nov 20 16:49:27 smallpond dhcpd: DHCPREQUEST for 192.168.0.145 from 00:1f:3a:12:e9:23 (dell-fe64c004e7) via p1p1
Nov 20 16:49:27 smallpond dhcpd: DHCPACK on 192.168.0.145 to 00:1f:3a:12:e9:23 (dell-fe64c004e7) via p1p1
If it is failing, you should see error messages which will indicate what is wrong. If you don't see anything then something is configured wrong and blocking dhcp requests.