How do I solve the DHCP configuration loss problem after device restart

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After the device restarts, there is a low probability that the DHCP configuration is lost.


Auto-Config is enabled by default. About two and a half minutes after the device restarts, the Auto-Config module checks whether the configuration file exists and determine whether the Auto-Config process is executed. If the save command is used at this time, files conflict. As a result, the Auto-Config module determines that the configuration file does not exist, and incorrectly executes the Auto-Config process. In this case, information about option fields or intermediate file required for executing the Auto-Config process is not configured on the DHCP server. Consequently, the Auto-Config process is suspended, and the DHCP configuration (including the configuration during configuration recovery and the Auto-Config process) is deleted.


After the device restarts, run the undo autoconfig enable command in the system view to disable Auto-Config.

Other related questions:
Why is the DHCP configuration lost on an AR after a while
If Auto-Config is enabled, the AR will periodically clear all DHCP configurations, causing DHCP configuration loss. To solve the problem, perform the following steps: 1. Run the undo autoconfig enable command on the AR to disable Auto-Config. 2. Wait for 4 or 5 minutes and run the display autoconfig-status command to check the Auto-Config status. If the value of Running is NO, the Auto-Config function has been disabled. 3. Perform the configuration and run the save command.

DHCP clients cannot obtain IP addresses. How do I solve this problem
Ensure that the DHCP configuration is correct, and reduce the IP address lease. If a long IP address lease is set, after all addresses in the address pool are allocated, addresses that are not required cannot be released immediately. As a result, other DHCP clients cannot obtain IP addresses.

Save the configuration of the S1728GWR-4P switch
Save the configuration of an S1728GWR-4P switch as follows: Choose System > File, select Config File from the Action drop-down list box, and save a configuration file. Perform the following steps: 1. Choose System > File. 2. Select Config File from the Action drop-down list box. 3. Select save the current configuration from the operation list. 4. Choose needs to be saved in the Save as file name, or rename files. 5. Click Apply.

Checking the restart reasons of an S series switch
the display reboot-info command to check restart reasons of S series switches (except S1700 switches). A switch may be restarted due to one of the following reasons: MANUAL: It is restarted by using the reboot command. POWER: It is restarted after being powered off. SCHEDU: It is restarted by using the schedule reboot command. OTHER: It is restarted due to either of the following reasons: 1. It is power recycled instantly, for example, the power cable is in bad contact or transient overvoltage and loss of voltage occurs. In this case, check whether the power cable is correctly connected to the switch. 2. An exception occurs in the system.

If SCHEDU or MANUAL is displayed in the command output, the switch is normally restarted. If POWER or OTHER is displayed, check whether any other devices using the same power supply system have reboot records around the time when the switch is restarted. If such reboot records are found, the switch's restart is caused by exceptions in the external power supply system. If no such reboot record is found, go to the next step . If the switch uses pluggable power modules, replace the power modules with power modules that can work normally to determine whether the power modules are faulty. If the switch uses built-in power modules, collect required information and contact Huawei technical support personnel if the external power supply system works properly. The information includes the outputs of the display version, display device, display reboot-info, display alarm urgent, and display power commands. (If pluggable power modules are used, the output of the display power command is not required.)


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