Communicating through the correct stack

If you are running multiple stacks, the first question to ask is whether the application is communicating through the correct stack. To identify the stack an application is using, you can look at the keyword TCPIPjobname in the TCPIP.DATA file. An application can also select a stack using the SETIBMOPT socket API.

You can use the Netstat parameter TCP/-p to specify the TCP/IP stack name for which you want Netstat report output. This lets you determine the characteristics of a particular stack.

Using the information provided by Netstat, you can change, if necessary, the hlq.PROFILE.TCPIP data set or the application configuration file. Alternatively, the application might need to communicate through another stack.

It is also helpful to understand the search order for configuration information used by z/OS® Communications Server. See z/OS Communications Server: IP Configuration Reference, "Understanding search orders of configuration information", for more information.

For more information about running multiple stacks, see z/OS Communications Server: IP Configuration Guide.