CORBA transactions through firewalls

Electronic commerce on the Internet is evolving from simple customer-to-business interactions, like online shopping, to complex business-to-business extranet applications. These applications typically require back-office processing in two or more organisations. CORBA provides abstractions that make it a good technology for building such applications. Transactions are a well known technique for ensuring the overall consistency of system state in the presence of the concurrent access and occasional failure that are likely in extranet applications. The use of CORBA transactions for supporting extranet applications is complicated by the use of firewalls. Conventional firewall technology operates by restricting access based on host address and port number, and does not suit CORBA, which abstracts away from these concepts. The paper describes the issues involved and shows how they can be addressed using an advanced CORBA object gateway.