By default, this file is in the folder /opt/ucd/server/conf/server.
For example, the server adds the property server.host, which specifies the IP addresses on which the server listens for JMS connections. In most cases, the server sets this property to the value 0.0.0.0, which means that the server listens for JMS connections on all IP addresses that it has available. You can specify a specific IP address in this property to limit the IP addresses that the server listens on.