Dynamic Host Controller Protocol, Which controlls the host in the form of protocol.
The port 67 and port 68 are used by DHCP and the DHCP clients.
dhcp has to be authorized
The use of a DHCP relay agent is an agent that relays DHCP between DHCP clients and DHCP servers on different IP networks. The DHCP relay agent is compliant with RFC 1542.
router (config)# ip dhcp servicerouter (dhcp-config)# ip dhcp pool router (dhcp-config)# network
(DHCP) Dynamic host Configuration Protocol. The Default Port Number is: for DHCP client : 546 for DHCP server : 547
yes DHCP require the authorization of the dhcp server before IP addresses can be allocated because until we authorize DHCP server the network does not know who is the dhcp server for the subnet. The DHCP server broadcasts the information to all.
A domain controller should have a static IP address so that it does not require DHCP(which is conveniently often ran on the domain controller) to come up onto the network. With a dynamically assigned IP address it would be possible for it to receive a different IP address when it requests its IP initially or when the lease expires. If this were to happen, all hosts on the network would essentially stop working because they would continue to try to access the domain controller via the old IP. If the domain controller fails to obtain an IP address via DHCP no users or computers would be able to access it, hence possibly causing your network to cease functioning.
Those are the four phases of acquiring an IP address via DHCP. More information would be needed to indicate which of the 4 phases are being used at this point.
dhcp-client
DHCP server configuration in /etc/dhcp/dhcpd.conf(FEDORA)or /etc/dhcpd.conf (RHEL).
DHCP Server can be a standalone server