iTable of Contents1 DHCP Overview··········································································································································1-1Introduction to DHCP ······························································································································1-1DHCP Address Allocation ·······················································································································1-2Allocation Mechanisms····················································································································1-2Dynamic IP Address Allocation Process ·························································································1-2IP Address Lease Extension ···········································································································1-3DHCP Message Format ··························································································································1-3DHCP Options·········································································································································1-4DHCP Options Overview ·················································································································1-4Introduction to DHCP Options ·········································································································1-4Self-Defined Options ·······················································································································1-5Protocols and Standards·························································································································1-82 DHCP Relay Agent Configuration ············································································································2-1Introduction to DHCP Relay Agent ·········································································································2-1Application Environment··················································································································2-1Fundamentals··································································································································2-1DHCP Relay Agent Support for Option 82 ······················································································2-2DHCP Relay Agent Configuration Task List ···························································································2-3Configuring the DHCP Relay Agent········································································································2-3Enabling DHCP ·······························································································································2-3Enabling the DHCP Relay Agent on an Interface ···········································································2-4Correlating a DHCP Server Group with a Relay Agent Interface····················································2-4Configuring the DHCP Relay Agent Security Functions ·································································2-5Configuring the DHCP Relay Agent to Send a DHCP-Release Request ·······································2-7Configuring the DHCP Relay Agent to Support Option 82······························································2-7Displaying and Maintaining DHCP Relay Agent Configuration·······························································2-9DHCP Relay Agent Configuration Examples··························································································2-9DHCP Relay Agent Configuration Example ····················································································2-9DHCP Relay Agent Option 82 Support Configuration Example····················································2-10Troubleshooting DHCP Relay Agent Configuration··············································································2-113 DHCP Client Configuration·······················································································································3-1Introduction to DHCP Client····················································································································3-1Enabling the DHCP Client on an Interface ·····························································································3-1Displaying and Maintaining the DHCP Client ·························································································3-2DHCP Client Configuration Example ······································································································3-24 DHCP Snooping Configuration ················································································································4-1DHCP Snooping Overview······················································································································4-1Function of DHCP Snooping ···········································································································4-1Application Environment of Trusted Ports ·······················································································4-2DHCP Snooping Support for Option 82···························································································4-3Configuring DHCP Snooping Basic Functions························································································4-4Configuring DHCP Snooping to Support Option 82················································································4-5
