Debugging problems with Ethernet connectivity

You can determine Ethernet connectivity problems by examining Ethernet statistics that are produced by the entstat command. Then, you can debug the problems by using the starttrace and stoptrace commands.

1. Verify that the source client logical partition can ping another client logical partition on the same system without going through the Virtual I/O Server.
   If this fails, the problem is likely in the client logical partition's virtual Ethernet setup. If the ping is successful, proceed to the next step.
2. Start a ping on the source logical partition to a destination machine so that the packets are sent through the Virtual I/O Server.
   This ping most likely fails. Proceed to the next step with the ping test running.
3. On the Virtual I/O Server, type the following command:

   entstat –all SEA_adapter

   where, SEA_adapter is the name of your Shared Ethernet Adapter.
4. Verify that the VLAN ID to which the logical partition belongs is associated with the correct virtual adapter in the VLAN IDs section of the output. Examine the ETHERNET STATISTICS for the virtual adapter for this VLAN and verify that the packet counts under the Receive statistics column are increasing.

   This verifies that the packets are being received by the Virtual I/O Server through the correct adapter. If the packets are not being received, the problem might be in the virtual adapter configuration. Verify the VLAN ID information for the adapters by using the Hardware Management Console (HMC).

5. Examine the ETHERNET STATISTICS for the physical adapter for this VLAN and verify that the packet counts under the Transmit statistics column are increasing.
   This step verifies that the packets are being sent out of the Virtual I/O Server.
   • If this count is increasing, then the packets are going out of the physical adapter. Continue to step 6.
   • If this count is not increasing, then the packets are not going out of the physical adapter, and to further debug the problem, you must begin the system trace utility. Follow the instructions in step 9 to collect a system trace, statistical information, and the configuration description. Contact service and support if you need to debug the problem further.
6. Verify that the target system outside (on physical side of Virtual I/O Server) is receiving packets and sending out replies.
   If this is not happening, either the wrong physical adapter is associated with the Shared Ethernet Adapter or the Ethernet switch might not be configured correctly.
7. Examine the ETHERNET STATISTICS for the physical adapter for this VLAN and verify that the packet counts under the Receive statistics column are increasing.
   This step verifies that the ping replies are being received by the Virtual I/O Server.
   If this count is not increasing, the switch might not be configured correctly.
8. Examine the ETHERNET STATISTICS for the virtual adapter for this VLAN and verify that the packet counts under the Transmit statistics column are increasing.
   This step verifies that the packet is being transmitted by the Virtual I/O Server through the correct virtual adapter.
   If this count is not increasing, start the system trace utility. Follow the instructions in step 9 to collect a system trace, statistical information, and the configuration description. Work with service and support to debug the problem further.
9. Use the Virtual I/O Server trace utility to debug connectivity problems.
   Start a system trace by using the starttrace command specifying the trace hook ID. The trace hook ID for Shared Ethernet Adapter is 48F. Use the stoptrace command to stop the trace. Use the cattracerpt command to read the trace log, format the trace entries, and write a report to standard output.