Server considerations

z/OS® Explorer consists of multiple permanently active servers, which can be started tasks or user jobs. These servers provide the requested services themselves or start other servers (as z/OS UNIX threads or user jobs) to provide the service. There is no specific start order. The only requirement is that the servers are up and running before the first user tries to connect.

The security mechanisms used by z/OS Explorer servers and services rely on the data sets and file systems they reside in being secure. This implies that only trusted system administrators should be able to update the program libraries and configuration files.
  • Common Services (FEKD) provides common services to other z/OS Explorer servers.
  • JES Job Monitor (JMON) provides all JES-related services.
  • Remote Systems Explorer (RSE) provides core services such as connecting the client to the host system and starting other servers for specific services. RSE consists of two logical entities:
    • RSE daemon (RSED), which manages connection setup.
    • RSE server, which handles individual client requests.
As documented in "TCP/IP ports" in Host Configuration Reference Guide (SC27-8438), certain host system services, and thus their ports, must be available for the client to connect to, and must be defined to your firewall protecting the host system. All other ports used by z/OS Explorer have host-only traffic. Listed below are the ports that are needed for external communication in a basic z/OS Explorer setup:
  • RSE daemon for client-host communication setup (using TCP), default port 4035.
  • RSE server for client-host communication (using TCP). By default, any available port is used, but the available ports can be limited to a specified range.