Troubleshooting NSX Traceflow
Article ID: 387914
Updated On: 02-13-2025
Products
Issue/Introduction
NSX Traceflow is a graphical troubleshooting tool used to show the components a packet traverses within the NSX environment. Traceflow allows you to identify the path (or paths) a packet takes to reach its destination or, conversely, where a packet is dropped along the way.
Further information about this tool in general can be found in Traceflow Documentation.
Suggestions for frequent uses of this tool can be found in Troubleshooting NSX Network Connectivity Issues.
Environment
VMware NSX
Resolution
While this is an excellent troubleshooting utility, it has limitations and several requirements:
- Traceflow are specially crafted packets injected into the data flow and processed by the networking components like any other packet, except the guest operating system of the sender/receiver does not see them.
- Traceflow does not work with HCX extended networks.
- Prior to NSX-T 3.2.0.1, NSX Traceflow can only provide insight for NSX Overlay Networks. Beginning in 3.2.0.1, Traceflow can be configured to function with NSX VLAN backed networks.
- For questions or concerns regarding enabling Traceflow for VLAN Backed networks, please see Does enabling In-band Network Telemetry (INT) for NSX Traceflow for VLAN-backed segments incur any overhead?
- After configuring Traceflow to function with NSX VLAN backed networks, only TCP/UDP and ICMP packets are supported.
- Beginning in NSX 3.2.1, Traceflow can be used in a Federation environment.
When troubleshooting Traceflow errors, relevant log messages can be found in the following locations
- NSX Manager
- /var/log/policy/policy.log
- /var/log/proton/nsxapi.log
- ESXi host
- /var/run/log/vmkernel.log
- /var/run/log/nsx-syslog.log
Known issues with Traceflow
Additional Information
When opening a case with Broadcom Support, please provide the following information:
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