Help Center > > FAQs> Connectivity> What Should I Do I If My ECS Fails to Obtain an IP Address?

What Should I Do I If My ECS Fails to Obtain an IP Address?

Updated at:Dec 09, 2020 GMT+08:00

  1. Check whether the DHCP function of the subnet is enabled (enabled by default).

    Switch to the subnet details page. If DHCP is disabled, you must manually configure a static IP address for the ECS by referring to step 4.

  2. Run the following command to check whether the dhclient process exists:

    ps -ef | grep dhclient

  3. If the dhclient process does not exist, log in to the ECS and try restarting the ECS NIC or sending a DHCP request.
    • Linux OS:

      Run the dhclient ethx command. If dhclient commands are supported, run the ifdown ethx;ifup ethx command. In the command, ethx indicates the ECS NIC, for example, eth0 and eth1.

    • Windows OS:

      Disconnect the network connection and connect it.

  4. If the DHCP client does not send requests for a long time, for example, the fault occurs again after the NIC restarts, you can use the following method to configure the static IP address.
    • Linux OS:
      1. Run the following command to open the /etc/sysconfig/network-scripts/ifcfg-eth0 file:

        vi /etc/sysconfig/network-scripts/ifcfg-eth0

      2. Modify the following configuration items in the /etc/sysconfig/network-scripts/ifcfg-eth0 file.


        IPADDR= #IP address

        NETMASK= #Subnet mask

        GATEWAY= #Gateway address

      3. Run the following command to restart the network service:

        service network restart

    • Windows OS:

      On the Local Area Connection Status tab, click Properties. In the displayed area, Select Internet Protocol Version 4 (TCP/IPv4) and click Properties. In the displayed area, enter the IP address, subnet mask, and the default gateway address.

  5. Check the ECS messages log in the /var/log/messages directory to troubleshoot the ECS.

    Search for the NIC MAC address and check whether processes that cause failures in obtaining IP addresses over DHCP exists.

  6. If the failure cannot be rectified after you perform the preceding operations, contact technical support.

    Provide the customer service with the ECS ID, the ID of the subnet used by the ECS, and the ID of the VPC used by the ECS.

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