H3C S5120-SI Series Configuration Manual

Also see for S5120-SI Series: Quick start guide Installation manual Operation manual Configuration guide Command reference

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H3C S5120-SI Series Configuration Manual Manual pdf 48 page image

48Figure 14 Configure trusted ports in a cascaded networkTable 3 describes roles of the ports shown in Figure 14.Table 3 Roles of portsDevice Untrusted port Trusted port disabled fromrecording binding entriesTrusted port enabled torecord binding entriesSwitch A GE1/0/1 GE1/0/3 GE1/0/2Switch B GE1/0/3 and GE1/0/4 GE1/0/1 GE1/0/2Switch C GE1/0/1 GE1/0/3 and Ethernet 1/4 GE1/0/2DHCP snooping support for Option 82Option 82 records DHCP client location information so the administrator can locate the DHCP client forsecurity control and accounting purposes.If DHCP snooping supports Option 82, it handles a client’s request according to the contents defined inOption 82, if any. The handling strategies are described in Table 4.If a reply returned by the DHCP server contains Option 82, the DHCP snooping device removes theOption 82 before forwarding the reply to the client. If the reply contains no Option 82, the DHCPsnooping device forwards it directly.