Configuring Site-to-Site Communication

GSLB site-to-site communication is between the remote procedure call (RPC) nodes that are associated with the communicating sites. A master GSLB site establishes connections with slave sites to synchronize GSLB configuration information and to exchange site metrics.

An RPC node is created automatically when a GSLB site is created, and is assigned an internally generated user name and password. The NetScaler appliance uses this user name and password to authenticate itself to remote GSLB sites during connection establishment. No configuration steps are necessary for an RPC node, but you can specify a password of your choice, enhance security by encrypting the information that GSLB sites exchange, and specify a source IP address for the RPC node.

The appliance needs a NetScaler owned IP address to use as the source IP address when communicating with other GSLB sites. By default, the RPC nodes use either a subnet IP (SNIP) address, but you might want to specify an IP address of your choice.

The following topics describe the behavior and configuration of RPC nodes on the NetScaler appliance:

Changing the password of an RPC node

You can secure the communication between sites in your GSLB setup by changing the password of each RPC node. After you change the password for the RPC node of the local site, you must manually propagate the change to the RPC node at each of the remote sites.

The password is stored in encrypted form. You can verify that the password has changed by using the show rpcNode command to compare the encrypted form of the password before and after the change.

To change the password of an RPC node by using the command line interface

At the command line, type the following commands to change the password of an RPC node:

set ns rpcNode <IPAddress> {-password}
show ns rpcNode  

Example:

> set rpcNode 192.0.2.4 -password mypassword
 Done
> show rpcNode
.
.
.
2)  IPAddress:  192.0.2.4 Password:  d336004164d4352ce39e
    SrcIP:  *                Secure:  OFF
Done
>

To unset the password of an RPC node by using the command line interface

To unset the password of an RPC node by using the CLI, type the unset rpcNode command, the IP address of the RPC node, and the password parameter, without a value.

To change the password of an RPC node by using the configuration utility

Navigate to System > Network > RPC, select the RPC node, and change the password.

Encrypt the exchange of site metrics

You can secure the information that is exchanged between GSLB sites by setting the secure option for the RPC nodes in the GSLB setup. With the secure option set, the NetScaler appliance encrypts all communication sent from the node to other RPC nodes.

To encrypt the exchange of site metrics by using the command line interface

At the command prompt, type the following commands to encrypt the exchange of site metrics and verify the configuration:

set ns rpcNode <IPAddress> [-secure ( YES | NO )]
show rpcNode

Example:

> set rpcNode 192.0.2.4 -secure YES
 Done
>
> show rpcNode
.
.
.
3)  IPAddress:  192.0.2.4 Password:  d336004164d4352ce39e SrcIP:  192.0.2.3     Secure:  ON
 Done
>

To unset the secure parameter by using the command line interface

To unset the secure parameter by using the CLI, type the unset rpcNode command, the IP address of the RPC node, and the secure parameter, without a value.

To encrypt the exchange of site metrics by using the NetScaler configuration utility

1. Navigate to System > Network > RPC and double-click a RPC node.
2. Select the Secure option, and click OK.

Configure source IP address for an RPC node

By default, the NetScaler appliance uses a NetScaler owned subnet IP (SNIP) address as the source IP address for an RPC node, but you can configure the appliance to use a specific SNIP address. If  a SNIP address is not available, the GSLB site cannot communicate with other sites. In such a scenario, you must configure either the NSIP address or a virtual IP (VIP) address as the source IP address for an RPC node. A VIP address can be used as the source IP address of an RPC node only if the RPC node is a remote node. If you configure a VIP address as the source IP address and remove the VIP address, the appliance uses a SNIP address.

Note

From NetScaler 11.0.64.x release onwards, you can configure the appliance to use GSLB Site IP address as the source IP address for an RPC node.

To specify a source IP address for an RPC node by using the command line interface

At the command prompt, type the following commands to change the source IP address for an RPC node and verify the configuration:

set ns rpcNode <IPAddress> [-srcIP <ip_addr|ipv6_addr|*>]
show ns rpcNode  

Example:

set rpcNode 192.0.2.4 -srcIP 192.0.2.3
Done
show rpcNode

IPAddress: 192.0.2.4 Password: d336004164d4352ce39e SrcIP: 192.0.2.3 Secure: OFF
Done

To unset the source IP address parameter by using the command line interface

To unset the source IP address parameter by using the CLI, type the unset rpcNodecommand, the IP address of the RPC node, and the srcIP parameter, without a value.

To specify a source IP address for an RPC node by using the NetScaler configuration utility

1. Navigate to System > Network > RPC and double-click a RPC node.
2. In the Source IP Address field, enter the IP address that you want the RPC node to use as the source IP address and click OK.

Important

The source IP address cannot be synchronized across the sites participating in GSLB because the source IP address for a RPC node is specific to each NetScaler appliance. Therefore, after you force a synchronization (using the sync gslb config –forceSync command or by selecting the ForceSync option in the GUI), you have to manually change the source IP addresses on the other NetScaler appliances.