You can use the default property to specify a default server in the server-list section. Valid values are true and false.
The following JSON configuration file example shows a default server.
{ "broker_list": " { \"settings\": { \"server-list\": [{ \"server\": \"123.456.1.1\", \"description\": \"View Server 1\", \"default\": true, \"username\": \"User1\", \"domain\": \"TestDomain1\" }]} }" }