Cisco 32369 Manual

Also see for Aironet 1000 Series: Deployment guide Hardware installation guide Hardware installation guide Hardware Upgrade Guide Manual

Contents

Cisco IOS DHCP Server 1Cisco IOS DHCP ServerFeature OverviewDynamic Host Control Protocol (DHCP) enables you to automatically assign reusable IP addressesto DHCP clients. The Cisco IOS DHCP Server feature is a full DHCP server implementation thatassigns and manages IP addresses from specified address pools within the router to DHCP clients.If the Cisco IOS DHCP Server cannot satisfy a DHCP request from its own database, it can forwardthe request to one or more secondary DHCP servers defined by the network administrator.Figure 1 shows the basic steps that occur when a DHCP client requests an IP address from a DHCPserver. The client, Host A, sends a DHCPDISCOVER broadcast message to locate a Cisco IOSDHCP Server. A DHCP server offers configuration parameters (such as an IP address, a MACaddress, a domain name, and a lease for the IP address) to the client in a DHSCPOFFER unicastmessage.Figure 1 DHCP Request for an IP Address from a DHCP ServerNote A DHCP client may receive offers from multiple DHCP servers and can accept any one of theoffers; however, the client usually accepts the first offer it receives. Additionally, the offer from theDHCP server is not a guarantee that the IP address will be allocated to the client; however, the serverusually reserves the address until the client has had a chance to formally request the address.The client returns a formal request for the offered IP address to the DHCP server in aDHCPREQUEST broadcast message. The DHCP server confirms that the IP address has beenallocated to the client by returning a DHCPACK unicast message to the client.Host ADHCPACK (unicast)DHCPREQUEST (broadcast)DHCPOFFER (unicast)DHCPDISCOVER (broadcast) Cisco IOSDHCP server32369