Operation Manual – DHCPH3C S7500E Series Ethernet Switches Chapter 2 DHCP Server Configuration2-14Option Option name CorrespondingcommandCommandparameter58 Renewal (T1) TimeValue expired hex59 Rebinding (T2) TimeValue expired hex66 TFTP server name tftp-server ascii67 Bootfile name bootfile-name ascii43 Vendor SpecificInformation — hexCaution:z Be cautious when configuring self-defined DHCP options because suchconfiguration may affect the DHCP operation process.z When you use self-defined option (Option 51) to configure the IP address leaseduration, convert the lease duration into seconds in hexadecimal notation.2.6 Configuring the DHCP Server Security FunctionsThis configuration is necessary to secure DHCP services on the DHCP server.2.6.1 Configuration PrerequisitesBefore performing this configuration, complete the following configuration on the DHCPserver:z Enable DHCPz Configure the DHCP address pool2.6.2 Enabling Unauthorized DHCP Server DetectionThere are unauthorized DHCP servers on networks, which reply DHCP clients withwrong IP addresses.With this feature enabled, when receiving a DHCP message with the siaddr field notbeing 0 from a client, the DHCP server will record the value of the siaddr field in themessage and the receiving interface. The administrator can use this information tocheck out any DHCP unauthorized servers.Follow these steps to enable unauthorized DHCP server detection:
