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Front & Back Side Handlers

An MPGW has two sides. The front side is how clients reach it; the back side is how it reaches the backend. Keeping them straight is essential.

Front Side Handlers (FSH)​

A Front Side Handler is the listener. It defines the protocol, the local address/interface, and the port the gateway accepts requests on, plus protocol-specific options.

Key points:

  • One MPGW can have multiple front-side handlers — e.g. HTTP and HTTPS and MQ all feeding the same policy.
  • Common handler types: HTTP, HTTPS (SSL/TLS), IBM MQ, TIBCO EMS, WebSphere JMS, FTP/SFTP, NFS, stateless raw TCP.
  • An HTTPS handler references a TLS server profile (Module 4) to terminate TLS.
  • Handlers are reusable objects — but each listens on a specific address/port, so two enabled handlers can't bind the same port.
enabled ≠ up

If a handler is enabled but its port is already taken, it will be operationally down. Recall the admin-state vs. op-state distinction from the object model.

The back side​

The back side is how the MPGW reaches the backend after processing.

  • Static backend — a fixed destination URL configured on the MPGW (e.g. https://orders.internal:443). Every request goes there.
  • Dynamic backend — no fixed URL; the processing policy sets the destination at runtime (typically with a route action or by setting the service variable for the backend URL). Use this for content-based routing.

Back-side connection options​

The back side also carries connection settings that matter in production:

  • TLS client profile — to re-encrypt to the backend (mutual TLS).
  • Timeouts and persistent connections — how long to wait, whether to reuse connections.
  • Load distribution — via a load balancer group object listing multiple backend members with a health-check and algorithm.

Putting it together​

A typical secure MPGW: an HTTPS front-side handler (with a TLS server profile) feeding a policy, with a static or dynamic backend reached over a TLS client profile. You'll build exactly this in Lab: Build an MPGW.

Knowledge Check

What does a Front Side Handler define?

You need to route requests to different backends based on the request URL. Which back-side approach do you use?