Configuring TCP/IP when the operating system is in restricted state

 

If you need to run TCP/IP while the operating system is in restricted state, you can use the method outlined in this topic.

 

Situation

As the network administrator, you need to obtain backup status reports for your system. When you are running backup procedures, the operating system must be in restricted state to prevent users from changing any configuration. Because you are remote, you access status reports using a personal digital assistant (PDA) device (or any TCP/IP networking device). The PDA uses a socket-enabled application that requires an active TCP/IP interface that is available to communicate with the system. To allow this communication, first start TCP/IP using special parameters. After you start TCP/IP, you will need to start a specific TCP/IP interface to allow access to the system. The following information provides more detail.

 

Restrictions

The following restrictions apply when the operating system is running in restricted state:

• You cannot start TCP/IP servers (STRTCPSRV CL command), because they require active subsystems.

• You can only start interfaces that are not attached to a network server description (NWSD) or a network interface description (NWID).

Configuration steps

1. Start TCP/IP using special parameters.

   In order to start TCP/IP while in restricted state, enter the command: STRTCP STRSVR(*NO) STRIFC(*NO) STRPTPPRF(*NO) STRIP6(*NO). These are the only parameters accepted when the operating system is in restricted state. The above command will start TCP/IP; however, it will not and cannot start TCP/IP application servers or IP interfaces.

2. Start a specific TCP/IP interface. After you start TCP/IP in restricted state, you can start the specific interface needed for your sockets-enabled application.

   1. Verify that the interface you want to start specifies a virtual IP address or uses a line description of *ELAN, *TRLAN, or *DDI.

      To view the line type for your interface, enter CFGTCP (the Configure TCP/IP command) at a command line interface and select Option 1 (Work with TCP/IP interfaces).

   2. Verify that the interface is not attached to an NWID or NWSD. Any other attempts will prompt an error message.

      To verify the interface is not attached to an NWID or NWSD, enter DSPLIND abc (where abc is the name of your line description) from a command line interface. Verify that the Resource name is not *NWID or *NWSD.

      If the interface is attached to an NWID or NWSD, then it is recommended you select a different interface.

   3. Start the interface. At a command line interface, enter STRTCPIFC INTNETADR('a.b.c.d'). Replace a.b.c.d with your interface IP address.

      Verify that STRTCPIFC INTNETADR(*AUTOSTART) is not specified.

3. Verify that the interface is active.

   Ping the specific interface for your application. There are very few TCP/IP related utilities that will operate in restricted state. However, ping and netstat can be used. For more information about using the ping and netstat commands, review Tools to verify your network structure within TCP/IP troubleshooting.

 

Parent topic:

Configuring TCP/IP