Refer to the exhibit.

The red dashed line for the UDP:137 flow in the NSX Intelligence information represents blocked communication. This indicates that the NSX Distributed Firewall has blocked the communication between the source and destination IP addresses on port 137.

For more information on NSX Intelligence and how to use it, please refer to the NSX-T Data Center documentation: https://docs.vmware.com/en/VMware-NSX-T-Data-Center/3.0/nsx-t-3.0-intelligence/GUID-C2B2AF2E-A76A-46B8-A67A-42D7A9E924A9.html