I run a HornetQ in standalone mode with its default configuration and I can connect to it from local system, If I want to connect from another system which configurations must be changed to make this possible?!
You first need to define what you mean by another system, did you mean another HornetQ instance, or did you mean another JMS Server?
What's the connection medium? you want a Bridge between hornetQ and other JMS Systems? look at the JMS Bridge on the hornetQ documentation
You want a client to connect to different Message servers? look at the Stomp protocol and several clients available from apache / activeMQ guys. HOrnetQ supports Stomp natively on the server's side.