3-3To improve security and avoid malicious attacks to the unused sockets, S4500 Ethernet switchesprovide the following functions:z UDP ports 67 and 68 used by DHCP are enabled/disabled only when DHCP is enabled/disabled.The implementation is as follows:z After the DHCP client is enabled by executing the ip address dhcp-alloc command, UDP port 68is enabled.z After the DHCP client is disabled by executing the undo ip address dhcp-alloc command, UDPport 68 is disabled.Examples# Configure VLAN-interface 1 to obtain an IP address through DHCP. system-viewSystem View: return to User View with Ctrl+Z.[Sysname] interface Vlan-interface 1[Sysname-Vlan-interface1] ip address dhcp-allocBOOTP Client Configuration Commandsdisplay bootp clientSyntaxdisplay bootp client [ interface Vlan-interface vlan-id ]ViewAny viewParametersvlan-id: ID of the VLAN interface.DescriptionUse the display bootp client command to display BOOTP client-related information, including theMAC address of the BOOTP client and the IP address obtained.Examples# Display the BOOTP client-related information. display bootp client interface Vlan-interface 1Vlan-interface1:Allocated IP: 192.168.0.2 255.255.255.0Transaction ID = 0x3d8a7431Mac Address 000f-e20a-c3efDefault router: 192.168.0.1
