Configure GSLB for DNS queries with NAPTR records 编辑

In a typical Global Server Load Balancing (GSLB) deployment, the Citrix ADC appliance receives DNS queries for A/AAAA records, selects the most appropriate GSLB service according to the configured load balancing method, and returns the service’s IP address as a reply to the DNS query. You can now configure the appliance to receive DNS queries for NAPTR records and respond with the list of services configured for a domain. The appliance also monitors the health of the services, and in the response it provides a list of only the services that are up.

Example:

In Telco deployments, you can configure a Citrix ADC appliance to receive DNS queries with NAPTR records from clients such as mobile management entities (MMEs), which play the role of a DNS resolver to discover all the services that are offered by the domain name. The appliance responds to the query with NAPTR records for all the services that are up. The MME can use this NAPTR response to run the S-NAPTR procedure to select the nodes on the basis of the service offered, colocation, topological closeness, and so on.

If multiple nodes qualify for selection, the MME can use the preference field in the NAPTR record from the Citrix ADC appliance to determine the node.

NAPTR Record Format

While responding to a DNS query with NAPTR record, a Citrix ADC appliance constructs a response NAPTR record for each GSLB service.

The following table lists the files in the NAPTR record:

Configuration procedure

For detailed GSLB configuration instructions, see Configuring Global Server Load Balancing (GSLB). Make sure that you do the following:

• Set the following parameters while adding the GSLB virtual server:
  • serviceType: ANY
  • dnsRecordType: NAPTR
  • lbMethod: CUSTOMLOAD

Example:

add gslb vserver gslb_vs ANY -dnsRecordType NAPTR -lbMethod CUSTOMLOAD
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