Routing server jobs based on client IP address

Some of the servers provided by IBM® i can be configured to run in a subsystem other than the default subsystem. A server can use subsystems that are shipped with the system or user-defined server subsystems. A server can also use multiple subsystems. The following steps show how to configure server subsystems using IBM Navigator for i.

To specify which subsystem server jobs will use:
  1. Select Network > Servers.
  2. Select the type of server that you want to configure. DDM and IBM i NetServer are TCP/IP servers. Central, Database, Data Queue, Files, Net Print, Remote Command, and Sign On are IBM i Access servers. The remaining steps use a subsystem from IBM i Access. The subsystem configuration steps are identical for each server.
  3. In the right pane, right-click on the server that you want to configure and select Properties, then switch to the Subsystems tab.
  4. From the Subsystems tab you can specify which subsystem you want this server's jobs to run in. There are different ways to configure the subsystems. Select the appropriate configuration method and complete the following instructions for your selection:
  • User server defaults

    Select this option if you want the server to use the default subsystem for all jobs using this subsystem.

  • All clients

    Select this option if all clients that use this server are to use the same subsystem and alternate action. All clients provides an easy way to subdivide the work done by the various servers into a subsystem by type of server. For example, you can have all clients for the database server use the DATABASE subsystem, all clients for the remote command server use the RMTCMD subsystem, etc.

    • The Subsystem list specifies the subsystem you want this server's jobs to run in. You can type in the ten character name of the subsystem you want to use, if it is not listed. If None is selected, the server jobs will perform the Alternate action.
    • The Alternate action list specifies what to do if the server jobs cannot run in the specified subsystem; for example if the subsystem is not active or if you want to prohibit certain users from using specific servers. Another example where the alternate action would be taken is when the necessary prestart jobs for the subsystem are not active. Possible values are Reject, and Start in current subsystem. When Reject is selected, the request will be rejected if it cannot run in the specified subsystem. When Start in current subsystem is selected, if the job cannot run in the specified subsystem, the job will attempt to run in the same subsystem that the server daemon is running in. For the database and file servers this will typically result in the request being run in the QSERVER subsystem. For other servers, this will result in requests being sent to QSYSWRK. See the Server table for more information on server jobs and the subsystems in which they run, including server and daemon jobs.
  • Specific clients

    Select this option if you want to set a unique subsystem configuration for specific clients. When you add specific client configuration, a <Public> entry will be added to the end of the list. The <Public> entry applies to all clients not included by the specific client entries you have added.

    There are different actions you can take to configure specific server subsystem clients.
    • Add - Select Add to add a client to the list. From Add Client you can specify the subsystem configuration for a specific client or a group of clients.

      IPv4 or IPv6 - Select the type of IP version you want to add.

      Description - Enter a text description of the client(s) that you are configuring.

      Client IP address or IP address range - Specify whether you want to use an individual IP address for a single client or a range of IP addresses for a group of clients. IP address ranges cannot overlap for the selected server.

      Subnet mask - The subnet mask specifies the subnet mask for this IP address. The subnet mask is a unique 32-bit integer that defines the part of the network where an interface attaches. The mask is expressed in the form xxx.xxx.xxx.xxx, where each field is the decimal representation of one byte (8 bits) of the mask. For example, the subnet mask with a hexadecimal representation is X'FFFFFF00' is expressed as 255.255.255.0.
      Note: If the entry is intended to only impact one IP address, the proper subnet mask would be 255.255.255.255.

      Subsystem - Specify the subsystem you want these client(s) to run in. You can type in the ten character name of the subsystem you want to use, if it is not listed. If None is selected, the client(s) will perform the Alternate action.

      Alternate action - The Alternate action list specifies what to do if the server jobs cannot run in the specified subsystem; for example if the subsystem is not active or if you want to prohibit certain users from using specific servers. Another example where the alternate action would be taken is when the necessary prestart jobs for the subsystem are not active. Possible values are Reject and Start in current subsystem. When Reject is selected, the request will be rejected if it cannot run in the specified subsystem. When Start in current subsystem is selected, if the job cannot run in the specified subsystem, the job will attempt to run in the same subsystem that the server daemon is running in. For the database and file servers this will typically result in the request being run in the QSERVER subsystem. For other servers, this will result in requests being sent to QSYSWRK. See the Server table for more information on server jobs and the subsystems in which they run, including server and daemon jobs.

    • Edit - Select the client record that you want to edit, and then select Edit to make changes to the selected client record.
    • Remove - Select the client record that you want to remove, and then select Remove to delete the selected client record from the list. You cannot remove the <Public> entry at the end of the list.
After all selections have been made, click OK to accept and apply the specified changes.