Almost all network firewalls allow HTTP traffic to pass, but some reject IIOP packets. When IIOP traffic is tunnelled inside of HTTP, your clients can connect to the EJB Server through a firewall that does not allow IIOP traffic to pass.
EJB Server’s Java client ORB performs HTTP tunnelling automatically using the designated IIOP port. No additional configuration or proxies are required. When connecting, the EJB Server client-side ORB first tries to open an IIOP connection to the specified address and port. If the IIOP connection fails, the ORB tries an HTTP-tunnelled connection to the same address and port. The default behavior is appropriate when some users connect through firewalls that require tunnelling and others do not; the same application can serve both types. If you know HTTP tunnelling is always required for a Java client, you can set the ORBHttp property to cause the ORB to use HTTP tunnelling without trying plain IIOP connections first..
