FQDN Configuration Example: DNS-Query-Origin Pool Selection

This page highlights configuration examples for the DNS-Query-Origin pool selection use case. For general information on virtual server pools and configuring load-balancing, refer to Virtual Server Pool.

The Virtual Server Pool Selection Method determines which virtual server or virtual server pool handles a request to an FQDN. When the DNS-Query-Origin method is selected, DNS queries will be load balanced to the pool with the same geographic information as the local DNS address, and the virtual server will respond according to the pool's preferred schedule methods.

Configuration Steps

The following is a high-level overview on how to create this configuration:

1. Create desired virtual servers and virtual server pool.
2. Go to GSLB > Service > FQDN and click Add FQDN. For additional details on the configuration steps on this page, refer to FQDN .
3. For the Virtual Server Pool Selection Method, select DNS-Query-Origin.
4. Manage Virtual Server Pool
   1. On the GSLB > Service > FQDN page, click the three dots in the corner of the newly created FQDN to expand the action menu, and select Manage Virtual Server Pool.
   2. Click Add Virtual Server Pool to add a virtual server pool that will handle requests to this FQDN. For additional details on the configuration steps on this page, refer to FQDN .

Create additional virtual server pools with other location(s) using the steps above.

5. Add the virtual servers into Virtual Server Pool. The FQDN will respond to the DNS query according to the Virtual Server Pool’s listed location(s) and DNS query’s source IP.

Note: If you want to use DNS-Query-Origin for matching Virtual Server Pool, all query source IP locations should be added to the location list or all corresponding IP/Netmasks or IP ranges should be added to the address group. Otherwise it uses Weight Round Robin method.

Example 1: Use only Location list

• Define one Location: United_States
• Assign Location United_States to virtual server pool: Virtual_Server_Pool_US
• Define second Location: Germany
• Assign Location Germany to virtual server pool: Virtual_Server_Pool_Germany

Result:

Queries from the United States will get replied from Virtual_Server_Pool_US, queries from Germany will get replied from Virtual_Server_Pool_Germany, queries other than these two countries will use Weight Round Robin between those two virtual server pools.

Example 2: Use Location list together with Address Group

Following the scenario set in Example 1, after having run the configuration for a while, you are finding that some particular source IP from the United States (here we are using 8.8.8.8 and 8.8.4.4 as an example) is not always getting replies from the Virtual_Server_Pool_US.

• Define an Address Group: United_States_IPs and add AddressNet 8.8.8.8/32 and AddressRange 8.8.4.4-8.8.4.4 as the members
• Assign Address Group United_States_IPs to virtual server pool Virtual_Server_Pool_US

Result:

Queries from 8.8.8.8 and 8.8.4.4 will also get replied from Virtual_Server_Pool_US.

Example 3: Use only Address Group

• Define one Address Group: Google_Resolvers
• Add AddressNet 8.8.8.8/32 and AddressRange 8.8.4.4-8.8.4.4 as the members
• Assign Address Group Google_Resolvers to virtual server pool Pool_for_Google
• Define another Address Group: any_IP
• Add AddressNet 0.0.0.0/0 as the member
• Assign Address Group any_IP to virtual server pool Pool_General

Result:

Queries from 8.8.8.8 and 8.8.4.4 will get replied from virtual server pool Pool_for_Google. Queries from other IP addresses will get replied from virtual server pool Pool_General.

Note: Although 8.8.8.8 and 8.8.4.4 are also included in the Address Group any_IP, the GSLB service is matching the virtual server pool by the sequence they are in the FQDN configuration. They will match the Address Group Google_Resolvers first, and get replied from Pool_for_Google.

Example 4: Use city-level location list

• Define one Location: CA_Sunnyvale
• Assign Location CA_Sunnyvale to virtual server pool Virtual_Server_Pool_CA_Sunnyvale
• Define second Location: CA_ Sacramento
• Assign Location CA_ Sacramento to virtual server pool Virtual_Server_Pool_CA_Sacramento

Result:

Queries from Sunnyvale will get replied from Virtual_Server_Pool_CA_Sunnvayle, queries from Sacramento will get replied from Virtual_Server_Pool_CA_Sacramento.