iii
DHCP relay agent support for Option 82 ·········································································································· 51
DHCP relay agent configuration task list ····················································································································· 51
Enabling DHCP ······························································································································································ 52
Enabling the DHCP relay agent on an interface ········································································································ 52
Specifying DHCP servers on a relay agent ················································································································· 52
Configuring the DHCP relay agent security functions ································································································ 53
Enabling the DHCP relay agent to record relay entries ···················································································· 53
Enabling periodic refresh of dynamic relay entries ··························································································· 53
Enabling DHCP starvation attack protection ······································································································ 54
Configuring the DHCP relay agent to release an IP address ···················································································· 55
Configuring Option 82 ················································································································································· 55
Displaying and maintaining the DHCP relay agent ··································································································· 56
DHCP relay agent configuration examples ················································································································· 56
DHCP relay agent configuration example ·········································································································· 56
Option 82 configuration example
······················································································································· 57
Troubleshooting DHCP relay agent configuration ······································································································ 58
Symptom
································································································································································· 58
Analysis ·································································································································································· 58
Solution ··································································································································································· 58
Configuring the DHCP client ····································································································································· 59
Enabling the DHCP client on an interface ··················································································································· 59
Configuring a DHCP client ID for an interface ··········································································································· 60
Enabling duplicated address detection ······················································································································· 60
Displaying and maintaining the DHCP client·············································································································· 61
DHCP client configuration example ····························································································································· 61
Network requirements··········································································································································· 61
Configuration procedure ······································································································································ 61
Verifying the configuration ··································································································································· 62
Configuring DHCP snooping····································································································································· 64
Overview········································································································································································· 64
Application of trusted and untrusted ports ·········································································································· 64
DHCP snooping support for Option 82 ·············································································································· 65
DHCP snooping configuration task list ························································································································ 66
Configuring basic DHCP snooping ······························································································································ 66
Configuring Option 82 ················································································································································· 67
Saving DHCP snooping entries ···································································································································· 68
Enabling DHCP starvation attack protection ··············································································································· 69
Enabling DHCP-REQUEST attack protection ··············································································································· 69
Configuring DHCP packet rate limit····························································································································· 70
Displaying and maintaining DHCP snooping ············································································································· 70
DHCP snooping configuration examples····················································································································· 71
Basic DHCP snooping configuration example ··································································································· 71
Option 82 configuration example
······················································································································· 72
Configuring the BOOTP client··································································································································· 74
BOOTP application ························································································································································ 74
Obtaining an IP address dynamically ························································································································· 74
Protocols and standards ················································································································································ 74
Configuring an interface to use BOOTP for IP address acquisition·········································································· 75
Displaying and maintaining BOOTP client ················································································································· 75
BOOTP client configuration example ·························································································································· 75
Network requirements··········································································································································· 75
Configuration procedure ······································································································································ 75