Device initialization exit program

The Telnet server application includes exit points that allow you to connect Telnet's sign-on and termination logic. You can use the Work with Registration Information (WRKREGINF) or Add Exit Program (ADDEXITPGM) commands to associate your custom exit program to an exit point.

If the Telnet server finds a program registered to one of the exit points for the server, it calls that program using parameters defined by the exit point. These parameters include things like IP address, user name, and virtual device name. Your custom exit program then processes the information. For example, logs a message and returns control to the Telnet server. On return, your exit program tells the system whether to accept or reject this client and any optional user or password overrides.

Each exit point has a name and an exit point interface. The exit point interface is a list of input and output parameters the Telnet server exchanges with your exit program. There are two exit points for the Telnet server:

Table 1. Required parameter group
No. Exit point interface Input or output? Parameters
1 User description information I/O Char(*)
2 Device description information I/O Char(*)
3 Connection description information Input Char(*)
4 Environment options Input Char(*)
5 Length of environment options Input Binary(4)
6 Allow connection Output Char(1)
7 Allow autosign-on Output Char(1)
  • Exit Point Name: QIBM_QTG_DEVINIT
  • Exit Point Format Name: INIT0100

The Telnet server optionally provides for selecting or setting the device name to be used over the Telnet session, and allows for a Telnet client to bypass traditional device initialization. Administrators might control these new features through the use of a new exit program, which optionally starts just after client session establishment. Several parameters are supplied to the exit program to be used in the decision process, and the exit program can set or change various parameters before returning to the Telnet server. You can optionally register a second exit program to start just before session termination. You can use this second exit program for session auditing or virtual device management.