dns_response probe uses UDP protocol even when TCP is selected

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

Why the dns_response probe uses UDP protocol even when TCP is selected?

Environment

Release : 20.x

Component : UIM - DNS_RESPONSE

Resolution

In general, the size of  DNS queries is less than 512 bytes so it always consists of a single UDP request. When the length of the query exceeds 512 bytes then larger UDP packets are used if the query failed then only sent again using the Transmission Control Protocol (TCP) i.e. if no response is received from the server within 5 seconds, the DNS query will be sent using the port 53 of TCP Protocol.

https://docs.microsoft.com/en-us/troubleshoot/windows-server/networking/dns-works-on-tcp-and-udp

currently it is not possible in the probe as it is protocol implementation.