update running outside of K8S

Author: gilesknap

docs/user/how-to/run_iocs.rst

@@ -17,11 +17,18 @@ will see the IOC running in a container:
 
 .. code-block:: bash
 
-    podman run -it -v $(pwd)/iocs/bl01t-ea-ioc-01/config:/repos/epics/ioc/config  ghcr.io/epics-containers/ioc-template-linux-runtime:23.3.3
+    podman run --net host -it --rm -v $(pwd)/iocs/bl01t-ea-ioc-01/config:/repos/epics/ioc/config  ghcr.io/epics-containers/ioc-template-linux-runtime:23.3.3
 
 What you have done here is pull down the generic ``ioc-template-linux-runtime``
 container image from the GitHub Container Registry and run it.
-The -it means it is an interactive terminal session.
+The ``-it`` means it is an interactive terminal session.  ``--rm`` means the
+container is removed when it exits, best for keeping your cache tidy.
+Note that you could also add ``-d`` to run the container in the background,
+you could then attach to it with the ``podman attach`` command.
+
+The ``--net host`` means the container will use the same network namespace as
+the host.  This is required because channel access protocol does not
+travel through a NAT to a container network (See `../explanations/net_protocols`)
 
 The -v mounts the local directory ``iocs/bl01t-ea-ioc-01/config`` into the
 container at ``/repos/epics/ioc/config``.  This is where the IOC expects to