Specifying IP version for underlying Java code

The OpenEdge NameServer and AppServer broker are implemented in Java. You must set Java system properties in the ubroker.properties file to properly configure IP communications, as described in the following table.

Table 56. Java properties for IPv6
Define the property ...	As ...	To configure ...
java.net.preferIPv4Stack	true	The AppServer or NameServer to only use IPv4 sockets. The AppServer or NameServer are not able to communicate with IPv6 clients.
java.net.preferIPv4Stack	false	The AppServer or NameServer to communicate with both IPv4 and IPv6 hosts.
java.net.preferIPv6Addresses	true	The default preference of IPv6 addresses over IPv4 addresses if IPv6 is available on the host system. This setting impacts the default hostname resolution for NameServer registration.
java.net.preferIPv6Addresses	false	The default preference of IPv4 addresses over IPv6 addresses if IPv6 is available on the host system. The AppServer will resolve the default hostname to an IPv4 address, even if an IPv6 address is configured.

You can add the Java system properties to your ubroker.properties file by adding the jvmArgs property. The jvmArgs property is not defined by default. The following example shows the jvmArgs property specified for a sample AppServer named doc: