What is Wi-Fi?

DHCP allows you to manage IP address allocation from a central location. You con configure a DHCP server to allocate IP addresses either for a single subnet or for multiple subnets. The DHCP server can assign client IP address configuration data to clients automatically. A lease is the length of time for which a DHCP client can use a dynamically assigned IP address configuration. Before the lease time expires, the client must either renew the lease or obtain a new lease form DHCP.DHCP managers the assignment and release of the IP address configuration data by leasing the IP address configuration to the client. The DHCP lease specifies how long the client can use the IP configuration data before returning it to the DHCP server and then renewing the data. The process of assigning IP address configuration data is known as the DHCP lease generation process. The process of renewing the IP address configuration data is known as the DHCP lease renewal process.The first time a DHCP client is added to the network, that client request IP address configuration data form a DHCP server. When the DHCP server receives the client request, the server selects an IP address form a range of addresses that the administrator has defined in its scope. The DHCP server offers this IP address configuration data to the DHCP client. If the client accepts the offer, the DHCP server leases the IP address to the client for a specified period of time. The client then uses the IP address configuration data to access the network.DHCP uses a four-step process to lease IP addressing information to DHCP clients. The four steps are named after the DHCP packet types:1. DHCP discover2. DHCP offer3. DHCP request4. DHCP acknowledgement or DHCP negative acknowledgement.DNS is a name resolution service. DNS resolves human-friendly addresses (such as www.microsoft.com) in to IP addresses (such as 192.168.0.1). Domain Name System (DNS) is a hierarchical distributed database that contains mappings of DNS host name to IP addresses. DNS enables user access to maps the alphanumeric host name to the numeric IP address. DNS also enables the system discovery of network services, such as e-mail server and domain controllers in the Microsoft? Active Directory? directory service.DNS is the foundation of the internet naming scheme, and it is also the foundation of an organization's Active Directory domain naming scheme. Without DNS, you would have to locate the IP Address of resources to access those resources. Because resource IP address can change, it would be difficult to maintain an accurate list of IP addresses and matching resources. DNS allows users to focus on alphanumeric names, which remain relatively constant in an organization, rather than on IP addresses.With DNS, the host name reside in a database that can be distributed among multiple servers, decreasing the load on any one server and providing the ability to administer this naming system on a per-domain name basis. DNS supports hierarchical names and allows registration of various data types in addition to the host name to IP address mapping that is used in the Hosts files. Because the DNS database is distributed, its size is unlimited, and performance does not degrade much when server are added.