H3C Technologies H3C S12500 Series Switches - Manual (Page 9)

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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 DHCP snooping ····································································································································· 59
Overview ········································································································································································· 59
Application of trusted and untrusted ports ·········································································································· 59
DHCP snooping support for Option 82 ·············································································································· 60
DHCP snooping configuration task list ························································································································ 61
Configuring basic DHCP snooping ······························································································································ 61
Configuring Option 82 ················································································································································· 62
Saving DHCP snooping entries ···································································································································· 63
Enabling DHCP starvation attack protection ··············································································································· 64
Enabling DHCP-REQUEST attack protection ··············································································································· 64
Displaying and maintaining DHCP snooping ············································································································· 65
DHCP snooping configuration examples ····················································································································· 65
Basic DHCP snooping configuration example ··································································································· 66
Option 82 configuration example ······················································································································· 66
Configuring DNS ······················································································································································· 68
Overview ········································································································································································· 68
Static domain name resolution ····························································································································· 68
Dynamic domain name resolution ······················································································································· 68
DNS proxy ····························································································································································· 69
DNS spoofing ························································································································································ 70
DNS configuration task list ············································································································································ 71
Configuring the IPv4 DNS client ·································································································································· 71
Configuring static domain name resolution ········································································································ 71
Configuring dynamic domain name resolution ·································································································· 71
Configuring the DNS proxy ·········································································································································· 72
Configuring DNS spoofing ··········································································································································· 72
Specifying the source interface for DNS packets ······································································································· 73
Configuring the DNS trusted interface ················································································································ 73
Displaying and maintaining IPv4 DNS ························································································································ 74
IPv4 DNS configuration examples ······························································································································· 74
Static domain name resolution configuration example ····················································································· 74
Dynamic domain name resolution configuration example ··············································································· 75
DNS proxy configuration example ······················································································································ 77
Troubleshooting IPv4 DNS configuration ···················································································································· 79
Symptom ································································································································································· 79
Solution ··································································································································································· 79