DHCP Option Sets

Introduction

A DHCP options set is a set of network configurations that will be delivered to your VM instance when its interface acquires an IP address using the DHCP protocol.

  1. DHCP options sets are associated with a project so that you can use them across all of your virtual private clouds (VPC).

  2. The supported options for a DHCP options set are as follows:

    1. Domain-name-servers - The IP addresses of up to four domain name servers, or ZadaraIaaSProvidedDNS. The default DHCP option set specifies ZadaraIaaSProvidedDNS. Although the custom DNS server is used, the DHCP-supplied DNS server to the VM instances will always be ZadaraIaaSProvidedDNS and the custom DNS will be queried indirectly by ZadaraIaaSProvidedDNS.

    2. Domain-name - This value is used to complete unqualified DNS hostnames. This is set by default to ‘symphony.local’.

    3. NTP-servers - The IP addresses of up to four Network Time Protocol (NTP) servers.

    4. Netbios-name-servers - The IP addresses of up to four NetBIOS name servers.

    5. Netbios-node-type - The NetBIOS node type (1, 2, 4, or 8).

How VPC passes DNS Servers via DHCP

When VPC DNS is enabled, the VPC DHCP service provides VMs with a pair of internal IPs as DNS servers. The VPC DNS service will look up any local zone records internally, and it will forward queries to the DNS servers provided in the DHCP Option Set for all external domains.

When VPC DNS is disabled, the VPC DHCP service provides VMs with the exact IPs of the DNS servers configured in the DHCP Option Set. In this case, DNS requests will go directly from VMs to the external DNS nameservers.

Creating a DHCP Option Set

To create a DHCP Option Set:

  1. Navigate to the Networking > DHCP Option Sets view.

  2. From the top toolbar, click Create.

  3. In the Create DHCP Options dialog, enter the following in the appropriate tab.

    • Details tab:

      • Name - name of the DHCP Options Set.

      • Description - optional description of the DHCP Options Set.

      • DNS Domain - valid DNS domain name (e.g. xxx.com)

    • Servers tab:

      • DNS Servers - IP of DNS Server associated with DHCP Options set being defined. Definition of DNS Server is optional.

      • NTP Servers - IP of NTP Server associated with DHCP Options set being defined. Definition of NTP Server is optional.

    • Netbios tab:

      • Netbios Node Type - The following types may be selected:

        • Type 1 - B-Node

        • Type 2 - P-Node

        • Type 4 - M-Node

        • Type 8 - H-Node

  4. Click Finish.

DHCP Options Set Operations

After creation of a DHCP Options Set, it will be displayed in the list in the Networking > DHCP Options Set view. The following operations can be performed by selecting a DHCP Options Set from the list, and clicking the appropriate icon from the top toolbar:

  • Modify - change name of the DHCP options set.

  • Attach VPC - attach DHCP options set to VPC.

  • Detach VPC - detach DHCP options set to VPC.

  • Delete - delete DHCP options set.