Capturing an IPDS Trace in AS400 / OS400 Environments

Overview

Network trace information may prove useful in the analysis and troubleshooting of print errors and anomalies in AS400 and other systems environments.

Note:  The sample host commands included in this article are based on V6R1 and specific only to AS/400 systems. Hence, host commands specific to customer's mainframe may need to be requested.

Click here for the English Only (.PDF) version of this procedure.

Before you begin

What you will need

Do the following to ensure the most reliable trace outcome. (Failure to follow these prerequisites will lead to an inaccurate trace and further complicate troubleshooting procedures.)

  1. A computer with Wireshark installed; click here to download this open source application.

  2. A dedicated network hub and not a switch or router; this enables Wireshark to accurately monitor the communication between printer and host.

Connection topology illustration

Illustration Key

  1. Dedicated network "Hub"

  2. PC hosting "Wireshark" application directly connected to hub

  3. Printer directly connected to hub

  4. AS400 or mainframe; make sure to connect the hub to the some WAN/LAN connection where the AS400 server resides.

Note:  There is no need to disconnect the AS/400 from the network during this setup.

Preparation and validating communication

Preparation

  1. Connect the network hub to the same network as the AS/400 server.

  2. Use an Ethernet (UTP) cable to connect the printer or printers that are to be tested to the hub.

    Note:  The printer may be offline for a few minutes until it reconnects (re-routes) its network connection.

  3. Use an Ethernet (UTP) cable to connect a Wireshark-equipped computer (laptop) to the hub .

  4. Verify that all devices (hub, PC and printer) are powered ON.

  5. Verify whether the printer has a valid IP address.

To locate the printer IP address:

  • Print the Network Settings page via Menus > Reports > Network Setup Page.
  • Or, view this value on the printer's dispaly via Menus > Network/Ports > Standard Network > Std Network Setup > TCP/IP.

Validating communication

  1. Verify whether the laptop can communicate with the printer with "NO" packet loss; e.g., a ping test should verify communication.

    To perform ping test, click Start > Run, enter cmd, press Enter or click OK.

  2. Verify that the AS/400 server can still print to the printer by releasing a test job from the server.

    • If AS/400 is unable to print then the AS/400 operator will have to verify that the IP address on the Device Description is the same as the printer's IP address (as gathered in Step 5 under Preparation above) and the AS/400 operator will have to edit the device description's IP address.

Explanation

The IP may have changed when printer was reattached to the network.

Trace Capture Steps

  1. Log in to the AS400.

  2. End the print writer to be used by typing "ENDWTR Name_of_writer".

  3. Wait or refresh until the writer status is END.

  4. Launch Wireshark application.

  5. Select theCapture menu and then Options.

  6. In the Capture Options dialog:

    1. Select interface as “Local”.

    2. Select Ethernet as the port to monitor.

    3. Place a checkmark next to "Capture packet in promiscuous mode".

    4. In the Capture Filter entry field, specify the filter string ip host (server) [host IP address] and printer IP address. For example: ip host 10.0.0.1 and 10.0.0.2.

    Note:  "Promiscuous Mode" This mode will capture ALL network traffic regardless of intended target.

  7. Click Start.

  8. Start the writer by typing "STRPRTWTR Name_of_writer".

  9. Wait (and refresh) until the writer status is STR.

  10. Send job to the printer; check printer to see whether job has started printing.

  11. Stop trace after job.

    • Monitor Wireshark Capture Dialog to make sure packets are being captured.
    • Click Stop after the job has completed printing.

  12. Click on File in menu bar, and then Save As to lauch save dialog.

Correct trace verification

A successful capture does not always indicate that the correct records have been captured. Thus, verification is necessary.

To verify:

  1. Open trace in Wireshark.

  2. Under Filter, input tcp.port == 5001, where 5001 is the port used for IPDS. Click here for illustration.

    Note:  Use 9100 for non-IPDS jobs.

  3. Click Apply.

  4. Verify that there are packets recorded for port 5001 (or 9100 and 9600 for non-IPDS).

  5. If packets are available, check the packet Source and Destination to make sure that the IP addresses that appear are from the AS/400 and the printer.

    For example, if the AS/400 IP is 157.184.116.27 and printer IP is 10.194.76.88, then the packets captured should show Source and Destination info like this (for bi-directional communication between server and printer). Click here for an illustration.

    • If you do not see the IP address of the AS/400, check to see whether you can ping the IP address from the laptop or PC.
    • If not, then you may be tracking the wrong IP address for the host. Check with the customer's network admin.

  6. Scroll to the end of the trace and see if the last packet is a FIN or RST, which signifies that job has completed. Click here for illustration.

  7. If any of the verification steps fail, see section below.

Submit trace for escalation

Send the trace file to TSC Level 3 who in turn sends it to PE.

Please send the trace with the following information:

  • Description of job that was performed when Tace A was captured.
  • Result of job that was performed when Tace A was captured.
  • Printer that AS/400 was printing to when Tace A was captured.

Example of good submission:

  • Trace1.pcap is the trace captured from a 20-page job sent to T654 that printed with missing bar code on page 3.
  • Trace2.pcap is the trace captured from the same job sent to T644 that printed correctly.”

Example of better submission:

“Captured the following traces of a 20-page job first sent to T654 and then to T644: T654_missing_barcode_pg3.pcap and T644_OK_barcode.pcap”

Both examples are good and acceptable. However, the second example is better because the filenames are descriptive enough to be easily understandable and unambiguous. That is, you know exactly which file is which after downloading from database or email.

Cannot get a good trace?

If you've performed the steps correctly but still fail verification (Step 3), repeat Steps 1 and 2 to see if there are items that you missed.

Common culprits

  • Use of a network switch instead of hub
  • Use of an incorrect IP address for the AS400 server or printer
  • Starting the trace after the job has printed
  • Stopping the trace too early (while job is still printing)
  • Customer's network topology uses multiple switches and routers preventing proper trace capture.

If you are not able to capture the trace, please report the problem to PE with the following info:

  1. Sample of trace that was captured so we can cross-verify.

  2. Description of what job was performed when trace in #1 was captured.

  3. Diagram or description of setup used during network trace capture

  4. Description of problems encountered during network trace capture.

  5. Description of any limitations or restrictions in customer's current network setup; e.g., customer does not want to detach printer from network, etc.

Hub Importance

You may need to set up port mirroring on the switch; otherwise, it may be necessary to use a simple hub to make the traffic reach the sniffing system. It should be noted that some devices advertised as hubs are in fact switches that use various filters or intelligence to prevent the workstations from seeing each other's packets; with this type of device, getting a good trace may not be possible.

LEGACY ID: HO3616
Was this article helpful?
Top