Known Issues

About the issue which the DHCP server of the logical network announces an unintended cache (resolver) DNS server address

Overview of the Issue

• The DHCP server of the logical network delivers an IP address (IP address of the DHCP server) that the customer does not intend as the IP address of the cache (resolver) DNS server.
• If the OS of the virtual server instance or the bare metal server acquires the IP address (DHCP server IP address) that the customer does not intend as the IP address of the cache (resolver) DNS server by DHCP, the global name space name can be resolved.* Enterprise Cloud 2.0 does not offer cache (resolver) DNS server.

Detail of the issue

Region

• JP3, JP4, JP5

Menu

• It occurs when both of the logical network and the server (virtual server or bare metal server) satisfy the following conditions.
• Logical network
  • Case 1. Create from the Logical Network menu and enter the following items in the subnet
    • DHCP enabled: Checking
    • DNS server: You have not entered an IP address in the text box
  • Case 2. Common Functions Common Functions Created from Gateway Menu All logical networks for gateway
• Server
  • Case 1. Create with virtual server menu, with the following settings
    • Interface: Connected to a logical network that meets the above conditions
    • OS: Obtained the IP address of the cache (resolver) DNS server by DHCP
  • Case 2. Bare metal server
    • Interface: Connected to a logical network that meets the above conditions
    • OS: Obtained the IP address of the cache (resolver) DNS server by DHCP

Confirmation method

• The method of checking whether the condition that this event meets is as follows.

• Logical network
  • Subnet
    • Cloud Computing Control Panel> Network> Logical Network> Please press subnet name from subnet.
      • DHCP Enabled: Please confirm whether it is valid on “Subnet Details” screen
      • DNS Server: It may be applicable when DNS server is “None” on “Subnet Details” screen. In case of “None”, it indicates whether the DNS server address has been delivered without entering the IP address in the DNS server, or 0.0.0.0 is entered to stop distributing the DNS server address.
• Virtual Server
  • Interface
    • Please press the instance name from the cloud computing control panel> server> virtual server> instance and check on the “instance details” screen
  • OS
    • Windows Server 2012 R2 / Windows Server 2016: Network and Sharing Center> Changing adapter settings> “Interface name connected to logical network”> Properties> Internet Protocol Version 4 (TCP / IPv4) Please check on Internet Protocol Version 4 (TCP / IPv4) Properties screen
    • Execute the following command at Red Hat Enterprise Linux / CentOS: Shell and check the output.
      • nmcli connection show <interface name connected to the logical network>
• Bare metal server
  • Interface
    • Cloud Computing Control Panel> Server> Please press the bare metal server name from the bare metal server and check on the “Bare Metal Server Details” screen.
  • OS
    • Windows Server 2012 R2: Network and Sharing Center> Changing Adapter Settings> “Logical (VLAN) Interface Connected to Logical Network”> Properties> Internet Protocol Version 4 (TCP / IPv4) Please check on the Properties of protocol version 4 (TCP / IPv4) screen
    • Execute the following command at Red Hat Enterprse Linux / CentOS: Shell and check the output
      • nmcli connection show <interface name connected to the logical network>

Solution

The solution is as follows.

1. When it is necessary to acquire the IP address of the cache (resolver) DNS server by DHCP
   • Please perform the following setting in “Edit Subnet”.
     • DNS Server: Enter the IP address of the cache (resolver) DNS server in the text box (* 1)
2. When it is not necessary to acquire the IP address of the cache (resolver) DNS server by DHCP
   • Please perform the following setting in “Edit Subnet”.
     • DNS Server: Check the “Disable DNS Server” check box. (* 2)

* 1 We do not offer cache (resolver) DNS server in Enterprise Cloud 2.0. Therefore, please specify the IP address of your internal DNS server and the IP address of the cache DNS server provided by the customer’s selected public DNS service.

* 2 In the case of API, enter 0.0.0.0 in the DNS server section.

Schedule

We plan to change the setting of the logical network of existing customers and stop delivery of an unintended cache (resolver) DNS server address.

If you need to take action before then, please take measures to deal with delivery / distribution of DNS server addresses referring to the above mentioned actions.