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Missing hostname in the server response





The hostname is present in the client request to the web server but is missing in the server's response.


Product: Flowmon Collector

Version: Any

Platform: Any

Question/Problem Description:

Why is the hostname missing in the server response?

Steps to Reproduce:  
Error Message:  
Defect Number:  
Enhancement Number:  

This behavior can be observed when "Add enabled L2 fields to the NetFlow identifiers" is enabled in the Configuration Center - Monitoring Ports - Advanced settings. 

This feature causes MAC addresses to be considered as a key field for creating flow records (standard key fields are IPs, ports, and L4 protocol), and in some cases (e.g. proxy is used in the HTTP/S communication), it can break flow pairs (request/response).
The hostname is present only in the client request. The flow exporter can fill the hostname to the server response, but when L2 key fields are enabled and MAC addresses are different for request and response, the communication is not paired; thus hostname is missing in the response.
Disabling "Add enabled L2 fields to the NetFlow identifiers" will cause correct traffic pairing, and the hostname will be visible in the response. 


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