DHCP assigned IP address has three mechanisms:
1 automatic allocation, DHCP server to assign a permanent IP address for the host, once the DHCP client for the first time successfully leased from the DHCP server to the IP address, you can use the permanent address.
2) dynamic allocation, the DHCP server specifies the IP address to a host having a time limit, the time expires, or when the host discard the clear address, which can be used by other hosts.
3 manual allocation, IP address of the client is specified by the network administrator, DHCP server assigned IP address will only tell the client host.
Three types of addresses distribution, only the dynamic allocation can be reused address of the client no longer needed.
Format of DHCP messages is based on the format of BOOTP messages, which requires a BOOTP relay agent apparatus having a function, and can interact with the DHCP server and BOOTP client. BOOTP relay agent function, so that no need to deploy a DHCP server on each physical network. RFC 951 and RFC 1542 BOOTP in agreement described in detail.
What is the best time to use DHCP?
Laptop computers within the company on many occasions to use! Because Laptop In use, when the time is set to DHCP client, then the domain on the inside as long as it is connected to a DHCP server can access the Internet, that the Department Laptop will be connected to the Internet up!
The number of computers within the domain of quite a long time: Another situation is when a very large number of computers within the domain, you do not have to approach a large one explained to set up their own network parameters, this time in order to save trouble, or to set up a DHCP Convenience.
Under what circumstances do not recommend using DHCP host?
Client will take the initiative to send a message to all machines on the domain at boot time, this time, if the domain is no DHCP host it? Then this Client-side computer sends a request message four times, the wait time is 1 second, the waiting time of the other three were 9,13,16 seconds. If a DHCP server is not responding, then after 5 minutes, Client computer will repeat this operation ends.
The computer in the domain, there are many machines actually use as a host, rarely Client needs, then it seems there is no need to set up DHCP.