VCP 5 Objective 6.2 – Perform Basic vSphere Network Troubleshooting

Objective 6.2 – Perform Basic vSphere Network Troubleshooting

For this objective I used the following resources:

  • VCP 5, Section 2 – Plan and Configure vSphere Networking
  • VMware Information Guide “VMware Virtual Networking Concepts”
  • VMware KB Article 1003893 (Troubleshooting Virtual Machine Network Connection Issues)
  • VMware KB Article 1001938 (ESX/ESXi Host Requirements for Link Aggregation)
  • VMware KB Article 1004048 (Sample Configuration of EtherChannel/Link Aggregation with ESX/ESXi and Cisco/HP Switches)
  • VMware KB Article 1005577 (What is beacon probing)


Verify Network Configuration

Refer to each objective under Section Two. Focus on the core concepts and configuration of both vNetwork Standard Switches and vNetwork Distributed Switches:

  • Port/dvPort Groups
  • Load Balancing and Failover Policies
  • VLAN Settings
  • Security Policies
  • Traffic Shaping Policies

For additional information read the VMware Information Guide “VMware Virtual Networking Concepts”. This document is based on VI3 but still does a good job with the core functions of a vStandard Switch.

Verify a Given Virtual Machine is Configured with the Correct Network Resources

Instead of duplicating work, refer to VMware KB 1003893, “Troubleshooting Virtual Machine Network Connection Issues”. More then enough information listed there.

Troubleshoot Virtual Switch and Port Group Configuration Issues

One key aspect to remember is when setting up Port Groups or dvPort Groups, spelling counts (as well as upper/lower case)! If a Port Group is spelled Test on one host and is spelled test on a second host vMotion will fail. Same holds true with Security Policies, if one vSwitch on a host is set to accept Promiscuous Mode and it is set to Reject on the other host, again vMotion will fail. Also, refer to the objectives under Section Two to be sure your switches are configured correctly.

Troubleshoot Physical Network Adapter Configuration Issues

This is pretty straight forward as there is not a lot of configuration done at the physical network layer. Be sure that your physical nics that are assigned to a virtual switch (vSwitch or dvSwitch) are configured the same (speed, vlans, etc) on the physical switch. If using IP Hash as your load balancing method make sure on the physical switch side link aggregation has been enabled. Refer to VMware KB 1001938 and VMware KB 1004048 for further details as well as examples. If using beacon probing for network failover detection it standard practice to use a minimum of three (or more) uplink adapters. See VMware KB 1005577 for further details.

Identify the Root Cause of a Network Issue Based on Troubleshooting Information

Using the above notes as well as the linked VMware KB articles one should be able to isolate issue to one of four areas:

  • Virtual Machine
  • ESX/ESXi Host Networking (uplinks)
  • vSwitch or dvSwitch Configuration
  • Physical Switch Configuration


  • vSphere Troubleshooting guide
  • vSphere Networking guide
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