To configure a secondary (backup) IP address on an interface, use the ip address command at the INTERFACE configuration level.Use the no ip address dhcp command to:• Release the IP address dynamically acquired from a DHCP server from the interface.• Disable the DHCP client on the interface so it cannot acquire a dynamic IP address from a DHCP server.• Stop DHCP packet transactions on the interface.When you enter the release dhcp command, the IP address dynamically acquired from a DHCP server is released from an interface.The ability to acquire a new DHCP server-assigned address remains in the running configuration for the interface. To acquire a new IPaddress, use the renew DHCP command in EXEC Privilege mode or the ip address dhcp command in INTERFACE Configurationmode.To manually configure a static IP address on an interface, use the ip address command. A prompt displays to release an existingdynamically acquired IP address. If you confirm, the ability to receive a DHCP server-assigned IP address is removed.To enable acquiring a dynamic IP address from a DHCP server on an interface configured with a static IP address, use the ip addressdhcp command. A prompt displays to confirm the IP address reconfiguration. If you confirm, the statically configured IP address isreleased. An error message displays if you enter the release dhcp or renew dhcp commands.To renew the lease time of the dynamically acquired IP, use the renew dhcp command on an interface already configured with a dynamicIP address.NOTE: To verify the currently configured dynamic IP address on an interface, use the show ip dhcp lease command. Theshow running-configuration command output only displays ip address dhcp. The currently assigned dynamic IP addressdoes not display.To configure and view an interface as a DHCP client to receive an IP address, use the following commands.1 Enter INTERFACE Configuration mode on an Ethernet interface.CONFIGURATION modeinterface type slot/port[/subport]2 Acquire the IP address for an Ethernet interface from a DHCP network server.INTERFACE modeip address dhcpDynamically assigned IP addresses can be released without removing the DHCP client operation on the interface on a switchconfigured as a DHCP client.3 Manually acquire a new IP address from the DHCP server by releasing a dynamically acquired IP address while retaining the DHCPclient configuration on the interface.EXEC Privilege moderelease dhcp interface type slot/port[/subport]4 Acquire a new IP address with renewed lease time from a DHCP server.EXEC Privilege moderenew dhcp interface type slot/port[/subport]To display DHCP client information, use the following show commands in EXEC Privilege mode.• To display statistics about DHCP client interfaces, use the show ip dhcp client statistics interface type slot/port[subport] command.• To clear DHCP client statistics on a specified or on all interfaces, use the clear ip dhcp client statistics {all |interface type slot/port[/subport]} command.294 Dynamic Host Configuration Protocol (DHCP)
