TEC Workbook - IBM

IBM Software
2.1.1 Client-Side (Front) Processing Phase
During this phase, the received message will be directed to the service object that is configured for the IP
address and port combination on which the message was received. Once the service object (such as a
Multi-protocol Gateway or XML Firewall) receives the message, a significant amount of processing of the
message occurs. For example:
● If SSL is configured for the service, SSL negotiation and decryption of the data stream will
occur.
● SOAP envelope validation.
● Protocol-specific actions such as HTTP header suppression or injection.
● Inspection for known XML threats.
This is not an exhaustive list, but gives an idea of some of the actions that occur upon receiving a
message. The results of these pre-processing steps could result in the message being rejected before
any message processing is even attempted.
2.1.2 Service Processing Phase
Once the client-side processing phase has completed and accepted the message, the message will be
passed to the service’s processing policy. This is often referred to as Multistep processing. A Processing
Policy is a list of rules that contain actions that can be applied to a message. Actions are specific
operations that are applied to a message such as encryption and decryption, message signing,
authentication, etc. As the request message passes through the processing policy, the actions are
applied to the message in a specified sequence, ultimately resulting in the message that will be passed
to the server-side processing phase.
2.1.3 Server-Side (Back) Processing Phase
If the message makes it to this phase, it has been accepted by the client-side phase and processed by
the service phase. It’s now ready to be sent to the backend server. Before sending though, some
additional steps may be required. Those steps may include:
● Establishing a new SSL connection to the back side server.
● Setting additional headers in the request.
● Mediating protocol versions (i.e. HTTP 1.1 to HTTP 1.0).
● Other protocol related tasks for WebSphere MQ, WebShere JMS, FTP, NFS, etc.
Once all of the server-side processing is complete, the message is sent to the backend destination.
2.1.4 Response Processing
When (and if) a response is received from the backend server, the three phases will occur again to verify
the validity of the response, execute a processing policy, and then forward the response back to the
original client. The processing phase can be configured to have separate rules for request and response
processing.
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