How to Delegate Subdomains in Microsoft DNS or BIND for Global Server Load Balancing on a NetScaler Appliance

本文包含关于授权的信息a Microsoft Domain Naming Service (DNS) or a Berkeley Internet Name Domain (BIND) for Global Server Load Balancing on a NetScaler appliance.

Background

When you use a NetScaler appliance for Global Server Load Balancing, the NetScaler appliance responds to the DNS queries for the configured hosts or sub-domains. Depending on the availability and load, the NetScaler appliance responds to the queries for the configured names with the best possible Global Server Load Balancing service IP address.

You can access the Microsoft DNS settings from theAdministrative Toolssub-menu of theStartmenu. Configure the example.com domain by using the DNS tool, as shown in the following screenshot:

Delegating a Microsoft DNS for Global Server Load Balancing on a NetScaler Appliance

To delegate a Microsoft DNS for Global Server Load Balancing on a NetScaler appliance, complete the following procedure:

1. Create the address records for the two NetScaler appliances that you want to handle delegation. These addresses are the Authoritative DNS (ADNS) addresses of each appliance. To create these address, complete the following sub-procedure:

   1. Open the DNS Manager and Right-click the domain.

   2. From the shortcut menu you can also selectNet Host (A).

   3. In theNamefield, type the NetScaler appliance name.

   4. In theIP addressfield, type the IP address of the appliance, as shown in the following screen shot:

      

   5. ClickAdd Host.

   6. Repeat the above procedure to add entries for the other NetScaler appliances as shown above.

2. Remove any entry from the host records, If there is any, for the service we are delegating.

3. Migrate the existing record for subdomain.example.com from an Address record to a delegation. To create a delegation, right-click the domain (example.com) and selectNew Delegationfrom the shortcut menu.

4. ClickNextin theDelegated Domain Namewizard.

5. Type the sub-domain under 'Delegated domain" you want to delegate.

6. ClickNext.

7. ClickAdd.

8. Select the NetScaler domain name that handles the delegation in theNew Resource Record, as shown in the following screenshot:

   

9. ClickOK.

10. Repeat Step 7 to Step 9 of this procedure to add the required NetScaler domains, as shown in the following screen shot:

    

11. ClickNext.

12. ClickFinish.

After completing the preceding procedure, the queries sent to the sub-domain of the DNS server either causes a recursive lookup to the NetScaler appliances or are responded to with the NetScaler records you have configured. To verify this, you can query the DNS server directly for the NetScaler appliance record of the sub-domain, as shown in the following screen shot:

Delegating a BIND for Global Server Load Balancing on a NetScaler Appliance

To delegate a BIND for Global Server Load Balancing on a NetScaler Appliance, complete the following procedure:
Note: In this procedure, it is assumed that you have already created the zone file and appropriately modified the named.conf file for the use. Also when configuring BIND, it is important to note that recursion needs to be ON. Recursion setting for BIND can be found in named.conf. If not, zone will not work and BIND DNS server will not be able to reach out to NetScaler for name resolution.

1. Edit thezonefile to add the required Address (A) records for the NetScaler appliances. The following are the sample entries to explain the concept:

   ns-east IN A 10.100.100.1 ns-west IN A 20.200.200.1

2. Remove the existing Address (A) records, other than the ones you added in the preceding step.

3. Create the required NameServer records. The following are the sample NameServer records:

   subdomain IN NS ns-east subdomain IN NS ns-west

4. Save and close the file.

5. Test the delegation to verify that the NetScaler appliance ADNS address is being returned.

Note: Depending on the DNS tool you use, the DNS query requests a recursive lookup. As a result, the DNS server, which holds the delegation, follows the delegation and requests an Address record from the NetScaler appliance. Therefore, if you have not yet completed the Global Server Load Balancing ADNS setup, you might observe a timeout. You can verify the appropriate setup of the DNS delegation by ensuring the lookup is set to type NS.

The following is the format for a sample nslookup:

> set type=ns > server 10.198.4.52 Default server: 10.198.4.52 Address: 10.198.4.52#53 > subdomain.example.com Server: 10.198.4.52 Address: 10.198.4.52#53 Non-authoritative answer: subdomain.example.com nameserver = ns-east.example.com. subdomain.example.com nameserver = ns-west.example.com. Authoritative answers can be found from: ns-east.example.com internet address = 10.100.100.1 ns-west.example.com internet address = 10.200.200.1