This page describes an older version of the product. The latest stable version is 16.4.

Multiple Network Cards

XAP can be configured for a multiple network card environment. For security reasons, network administrators may choose to configure their network with limited access of one card open to outside connections, and another card for internal connections. The default network card configuration is not always set to the network card used for internal connection, and thus needs to be configured.

The java.rmi.server.hostname system property is used to resolve the NIC address for all services, which bind to a specific network interface, e.g. Jini unicast discovery lookup host, Webster, etc. More specifically, multicast and unicast discovery both use this property to limit and set the desired network interface card.

The XAP_NIC_ADDRESS environment variable is exposed as part of the <XAP Root>\bin\setenv script. By default, this value is configured to use the hostname of the machine.

Since the java.rmi.server.hostname system property is set by default to the XAP_NIC_ADDRESS environment variable, and propagated across all product components/layers; in most cases, you don’t need to edit the setenv file or any other configuration file.

To apply this configuration easily, the XAP_NIC_ADDRESS variable can be passed at the script level of each node startup, before the call to setenv, thus overriding the default value set for this property in the setenv script.


Make sure your network and machines running XAP are configured to have multicast enabled. Refer to Multicast Configuration for details on how to enable multicast.

Configuring XAP for Multiple NICs


This procedure lists the general configuration process steps that are required to test and configure the Multi-NIC settings in XAP. Refer to these sections only if the out-of-the-box settings fail to work.

  1. Viewing the network interface information (optional)
  2. Specifying a network card to bind the lookup service
  3. Limiting use to a specific network interface (multicast only) (optional)
  4. Using unicast to register with a lookup service (optional)
  5. Testing your configuration
  6. Troubleshooting your configuration, if you experience problems
See also:
For more details, refer to the Advanced Multi-NIC Configuration section.