3Com 4500G Family Configuration Manual page 242

1 DHCP Overview··········································································································································1-1
Introduction to DHCP ······························································································································1-1
DHCP Address Allocation ·······················································································································1-2
Allocation Mechanisms····················································································································1-2
Dynamic IP Address Allocation Process ·························································································1-2
IP Address Lease Extension ···········································································································1-3
DHCP Message Format ··························································································································1-3
DHCP Options·········································································································································1-4
DHCP Options Overview ·················································································································1-4
Introduction to DHCP Options ·········································································································1-4
Self-Defined Options ·······················································································································1-5
Protocols and Standards·························································································································1-8
2 DHCP Relay Agent Configuration ············································································································2-1
Introduction to DHCP Relay Agent ·········································································································2-1
Application Environment··················································································································2-1
Fundamentals··································································································································2-1
DHCP Relay Agent Support for Option 82 ······················································································2-2
DHCP Relay Agent Configuration Task List ···························································································2-3
Configuring the DHCP Relay Agent········································································································2-3
Enabling DHCP ·······························································································································2-3
Enabling the DHCP Relay Agent on an Interface ···········································································2-4
Correlating a DHCP Server Group with a Relay Agent Interface····················································2-4
Configuring the DHCP Relay Agent Security Functions ·································································2-5
Configuring the DHCP Relay Agent to Send a DHCP-Release Request ·······································2-7
Configuring the DHCP Relay Agent to Support Option 82······························································2-7
Displaying and Maintaining DHCP Relay Agent Configuration·······························································2-9
DHCP Relay Agent Configuration Examples··························································································2-9
DHCP Relay Agent Configuration Example ····················································································2-9
DHCP Relay Agent Option 82 Support Configuration Example····················································2-10
Troubleshooting DHCP Relay Agent Configuration··············································································2-11
3 DHCP Client Configuration·······················································································································3-1
Introduction to DHCP Client····················································································································3-1
Enabling the DHCP Client on an Interface ·····························································································3-1
Displaying and Maintaining the DHCP Client ·························································································3-2
DHCP Client Configuration Example ······································································································3-2
4 DHCP Snooping Configuration ················································································································4-1
DHCP Snooping Overview······················································································································4-1
Function of DHCP Snooping ···········································································································4-1
Application Environment of Trusted Ports ·······················································································4-2
DHCP Snooping Support for Option 82···························································································4-3
Configuring DHCP Snooping Basic Functions························································································4-4
Configuring DHCP Snooping to Support Option 82················································································4-5
Table of Contents
i