H3C Technologies H3C S12500-X Series Switches - Manual (Page 8)

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Enabling the DHCP relay agent to record relay entries ···················································································· 54
Enabling periodic refresh of dynamic relay entries ··························································································· 54
Enabling DHCP starvation attack protection ······································································································ 55
Configuring the DHCP relay agent to release an IP address ···················································································· 56
Configuring Option 82 ················································································································································· 56
Setting the DSCP value for DHCP packets sent by the DHCP relay agent ······························································· 57
Displaying and maintaining the DHCP relay agent ··································································································· 57
DHCP relay agent configuration examples ················································································································· 57
DHCP relay agent configuration example ·········································································································· 57
Option 82 configuration example ······················································································································· 58
Troubleshooting DHCP relay agent configuration ······································································································ 59
Symptom ································································································································································· 59
Analysis ·································································································································································· 59
Solution ··································································································································································· 59
Configuring the DHCP client ····································································································································· 60
Enabling the DHCP client on an interface ··················································································································· 60
Configuring a DHCP client ID for an interface ··········································································································· 60
Enabling duplicated address detection ······················································································································· 61
Setting the DSCP value for DHCP packets sent by the DHCP client ········································································· 61
Displaying and maintaining the DHCP client ·············································································································· 62
DHCP client configuration example ····························································································································· 62
Network requirements ··········································································································································· 62
Configuration procedure ······································································································································ 63
Verifying the configuration ··································································································································· 63
Configuring DHCP snooping ····································································································································· 65
Overview ········································································································································································· 65
Application of trusted and untrusted ports ·········································································································· 65
DHCP snooping support for Option 82 ·············································································································· 66
DHCP snooping configuration task list ························································································································ 67
Configuring basic DHCP snooping ······························································································································ 67
Configuring Option 82 ················································································································································· 68
Saving DHCP snooping entries ···································································································································· 69
Enabling DHCP starvation attack protection ··············································································································· 70
Enabling DHCP-REQUEST attack protection ··············································································································· 71
Setting the maximum number of DHCP snooping entries ·························································································· 71
Configuring DHCP packet rate limit ····························································································································· 72
Displaying and maintaining DHCP snooping ············································································································· 72
DHCP snooping configuration examples ····················································································································· 73
Basic DHCP snooping configuration example ··································································································· 73
Option 82 configuration example ······················································································································· 74
Configuring DNS ······················································································································································· 76
Overview ········································································································································································· 76
Static domain name resolution ····························································································································· 76
Dynamic domain name resolution ······················································································································· 76
DNS configuration task list ············································································································································ 77
Configuring the IPv4 DNS client ·································································································································· 78
Configuring static domain name resolution ········································································································ 78
Configuring dynamic domain name resolution ·································································································· 78
Configuring the IPv6 DNS client ·································································································································· 79
Configuring static domain name resolution ········································································································ 79
Configuring dynamic domain name resolution ·································································································· 79
Specifying the source interface for DNS packets ······································································································· 80
Configuring the DNS trusted interface ························································································································· 81