TCP/IP communications trace

 

One of the uses of the trace tool is to show the clear text of a transmission in an environment where the data is encrypted.

The trace data is captured before encryption at the sender, and after encryption at the receiver. However, the trace tool is useful in other environments as well. You can only use this function when you are using TCP/IP for communication.

To use the Trace TCP/IP Application (TRCTCPAPP) command, have a user profile with *SERVICE special authority. To start the trace, enter the following line:

TRCTCPAPP *DDM

If you want to restrict the trace to a certain port, for example port 448 for SSL, follow this example:

TRCTCPAPP *DDM *ON RMTNETADR(*INET *N '255.255.255.255' 448)

After the communication that you are tracing has finished, run the following command and look at the resulting spooled file:

TRCTCPAPP *DDM *OFF

If you traced more than one connection, you will need to locate and match your spool files to each QRWTSRVR job. The spool file name is QZBSTRC and the job is QRWxxxxxx, where xxxxxx is the job number placed in the user data for the spool file.

Restriction for use with *DDM application

When you use the Trace TCP/IP Application (TRCTCPAPP) command with the *DDM application, the maximum amount of data you can trace for a single sent or received message is limited to 6000 bytes.

• TCP/IP communication trace formatting
  The Trace TCP/IP Application (TRCTCPAPP) command can be used to break down DRDA^® and DDM flows into an easier-to-read logical representation. It also displays the information in ASCII which can be of help in unlike environments.

 

Parent topic:

Getting data to report a failure

 

Related concepts

Communications trace

 

Related reference

Trace TCP/IP Application (TRCTCPAPP) command