Use Traceflow to inspect the path of a packet as it travels from one logical port on the logical network to another logical port on the same network. Traceflow traces the transport node-level path of a packet injected at a logical port. The trace packet traverses the logical switch overlay, but is not visible to interfaces attached to the logical switch. In other words, no packet is actually delivered to the test packet’s intended recipients.


  1. From your browser, log in with admin privileges to an NSX Manager at https://nsx-manager-ip-address.
  2. Navigate to the Traceflow screen. You have two options.
    • Select Tools > Traceflow from the navigation panel.
    • Select Switching from the navigation panel, click the Ports tab, select a VIF-attached port and click Actions > Traceflow
  3. Select a traffic type.
    The choices are Unicast, Multicast, and Broadcast.
  4. Specify the source and destination information according to the traffic type.
    Traffic Type Specify Source Information Specify Destination Information
    Unicast Select a VM and a virtual interface.

    The IP address and MAC address are displayed if VMtools is installed in the VM or if the VM is deployed using OpenStack plug-in (address bindings will be used in this case). If the VM has more than one IP address, select one from the drop-down menu.

    If the IP address and MAC address are not displayed, enter the IP address and MAC address in the text boxes.

    This will also apply to Multicast and Broadcast.

    Select either VM Name or IP-MAC from the "Type" drop-down menu.
    • If VM Name is selected, select a VM and virtual interface. Select or enter an IP address and a MAC address
    • If IP-MAC is selected, select the trace type (Layer 2 or layer 3). If trace type is Layer 2, enter an IP address and a MAC address. If trace type is Layer 3, enter an IP address.
    Multicast Same as above. Enter an IP Address. It must be a multicast address from -
    Broadcast Same as above. Enter a subnet prefix length.
  5. (Optional) Click Advanced to see the advanced options.
  6. (Optional) In the left column, enter the desired values or input for the following fields:
    Option Description
    Frame Size e.g. 128
    TTL e.g. 64
    Timeout (ms) e.g. 10000
    Ethertype e.g. 2048
    Payload Type Select an option from the dropdown menu.
    Payload Data Payload formatted based on selected Payload Type (Base64, Hex, Plaintext, Binary, or Decimal)
  7. (Optional) In the left column under "Protocol", select a protocol from the "Type" drop-down menu.
  8. (Optional) Based on the protocol selected, complete the associated steps in the following table.
    Protocol Step 1 Step 2 Step 3
    TCP Enter a source port. Enter a destination port. Select the desired TCP Flags from the drop-down menu.
    UDP Enter a source port. Enter a destination port. N/A
    ICMP Enter an ICMP ID. Enter a sequence value. N/A
  9. Click Trace.
    Information about the connections, components, and layers is displayed. The output includes a table listing Observation Type (Delivered, Dropped, Received, Forwarded), Transport Node, and Component, and a graphical map of the topology if unicast and logical switch as a destination are selected. You can apply a filter ( All, Delivered, Dropped) on the observations that are displayed. If there are dropped observations, the Dropped filter is applied by default. Otherwise, the All filter is applied. The graphical map shows the backplane and router links. Note that bridging information is not displayed.