Steps for diagnosing problems connecting to a server

Determine the source of the problem in connecting to a server.

Perform the following steps:

1. Verify that TCP/IP is running correctly on your host. Use Ping loopback, then Ping one of your home addresses. For information about the Ping command, see z/OS Communications Server: IP System Administrator's Commands.
2. Verify that the server application is operational. See Steps for verifying server operation for more information.
3. Verify IP routing to the server or the client. If you are not using policy-based routing, see Steps for verifying IP routing to a destination when not using policy-based routing for more information. Otherwise, see Steps for diagnosing problems with IP routing to a destination when using policy-based routing for more information.
4. Use the DISPLAY TCPIP,,NETSTAT,ACCESS,NETWORK command to determine whether network access has been configured on the TCP/IP stack. See z/OS Communications Server: IP System Administrator's Commands for more information about this command. If network access control is enabled, then the server might not be permitted to send or receive data on a socket. See Steps for verifying network access to determine whether network access controls are impacting the server application.
5. Verify IP security protection for the server. If IP security is enabled, then IP traffic to or from the server might not be permitted to flow. See Steps for diagnosing IP security problems to determine whether IP security controls are impacting the server application.