UDP and ports 67 and 68.
See related link. You can use MyLanViewer and detect DHCP servers.
DHCP, or Dynamic Host Configuration Protocol, is a language computers use to ask for an IP address when first connecting to a network. It is used to assign IP addresses and network information so the new computer can connect to various other servers running on the network. A residential router or gateway automatically performs these functions. It is importand that each network only include one DHCP server, or conflicts could occur. Depending on circumstances and the way the server was setup, it may accept or deny the request. The latter case being the computer will not be able to communicate on the network.
dhcp
DHCP is good if you've got a network that changes constantly. If you owned a hotel that offered free in-room high-speed Internet over Ethernet, DHCP would make your life much simpler: instead of issuing a static IP address to every guest, you'd just tell them to set their laptops to use DHCP and plug into the jack in the wall. If you're running a network that doesn't change much over time, you can still use DHCP but I think it's kinda silly--it's as easy to plug in an IP address and subnet mask as it is to use DHCP.
By default, these are ports 1717 and 2504 UDP.
According to Microsoft:How to use automatic TCP/IP addressing without a DHCP server"A Windows-based computer that is configured to use DHCP can automatically assign itself an Internet Protocol (IP) address if a DHCP server is not available. For example, this could occur on a network without a DHCP server, or on a network if a DHCP server is temporarily down for maintenance."For more information, see Related Links, below.
ipconfig /release
.What is the difference between FTP and TFTP?
Yes, you can.
yes, one can configure two dhcp server on a same network. But for doing this, one has to define different scopes in both dhcp server in order to avoid ip address conflict. Eg. one can configure a scope for a lan with network address of 10.0.0.0 as- 10.0.0.10- 10.0.0.100 in one dhcp server. while other scope would be 10.0.0.101-10.0.0.200 . In this way we can have to dhcp servers on a same network. Which ever dhcp server receives the request for the ip address will provide the ip address. IN case for servers, one can use mac bindingin both servers so that they obtain same ip address
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.