ADC

Load balance DNS servers

August 20, 2024

Contributed by:

C C

When you request DNS resolution of a domain name, the Citrix ADC appliance uses the configured load balancing method to select a DNS service. The DNS server to which the service is bound then resolves the domain name and returns the IP address as the response. The appliance can also cache DNS responses and use the cached information to respond to future requests for resolution of the same domain name. Load balancing DNS servers improves DNS response times.

The following diagram describes the topology of a load balancing configuration that load balances a group of DNS services.

Figure 1. Basic Load Balancing Topology for DNS Servers

basic-topology

In the diagram, the services Service-DNS-1, Service-DNS-2, and Service-DNS-3 are bound to the virtual server Vserver-LB-1. The virtual server Vserver-LB-1 forwards client requests to a service using the least connection load balancing method. The following table lists the names and values of the basic entities configured on the appliance.

Entity type	Name	IP address	Port	Protocol
Virtual Server	Vserver-LB-1	10.102.29.13	53	DNS
Services	Service-DNS-1	10.102.29.14	53	DNS
	Service-DNS-2	10.102.29.15	53	DNS
	Service-DNS-3	10.102.29.16	53	DNS
Monitors	monitor-DNS-1	None	None	None

The following diagram shows the load balancing entities and the values of the parameters that need to be configured on the appliance.

Figure 2. Load Balancing DNS Servers Entity Model

entity-model

To configure a basic DNS load balancing setup, see Setting Up Basic Load Balancing. Follow the procedures to create services and virtual servers of type DNS, naming the entities and setting the parameters using the values described in the previous table. When you configure a basic load balancing setup, the default ping monitor is bound to the services. For instructions on binding a DNS monitor to DNS services, you can also see Binding Monitors to Services. The following procedure describes the steps to create a monitor that maps a domain name to the IP address based on a query.

To configure DNS monitors by using the command line interface

At the command prompt, type:

add lb monitor <monitorName> DNS -query <domainName> -queryType <Address|ZONE> -IPAddress <ipAddress>
<!--NeedCopy-->

Example:

add lb monitor monitor-DNS-1 DNS -query www.citrix.com -queryType Address -IPAddress 10.102.29.66

add lb monitor monitor-DNS-2 DNS -query www.citrix2.com -queryType Address -IPAddress
1000:0000:0000:0000:0005:0600:700a::888b-888d
<!--NeedCopy-->

To configure DNS monitors by using the configuration utility

Navigate to Traffic Management > Load Balancing > Monitors.
Create a monitor of type DNS, and in Special Parameters, specify a query and query type.

The official version of this content is in English. Some of the Cloud Software Group documentation content is machine translated for your convenience only. Cloud Software Group has no control over machine-translated content, which may contain errors, inaccuracies or unsuitable language. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, suitability, or correctness of any translations made from the English original into any other language, or that your Cloud Software Group product or service conforms to any machine translated content, and any warranty provided under the applicable end user license agreement or terms of service, or any other agreement with Cloud Software Group, that the product or service conforms with any documentation shall not apply to the extent that such documentation has been machine translated. Cloud Software Group will not be held responsible for any damage or issues that may arise from using machine-translated content.

Load balance DNS servers

August 20, 2024

Contributed by:

C C

August 20, 2024

Contributed by:

C C

Load balance DNS servers

To configure DNS monitors by using the command line interface

To configure DNS monitors by using the configuration utility

In this article