How can EJB's be accessed through Firewalls?

With RMI over IIOP, RMI based EJB servers can be mixed with RMI based or CORBA Based EJB servers because everyone are propagating context information using IIOP.

RMI has the ability to tunnel through Firewalls. This is very slow and arduous process, and it is really a security loophole. Special IIOP Firewall Proxies are developed and available that will permit IIOP traffic to pass through. If you are using IIOP protocol, any RMI or CORBA code you write will navigate the firewall.

Limitations are the effectiveness of the proxies. ie you will have to have proxies on both client and server.

One cant set up a B2C site with a IIOP proxy thinking that will be a solution for the problem. Only for limited applications where the server and client can be controlled, IIOP proxy add value.

IONA provides a proxy called WonderWall and Borland provides the VisiBroker GateKeeper.