DNS Client 1.2.4 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The application lies within Developer Tools, more precisely Webmaster Tools. The actual developer of this free software for Mac is Sergii Kryvoblotskyi. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
DNS Client is a networking developer tool for debugging Domain Name Servers. The application gives an ability to create requests in human readable format and interprets responses. The utility supports all known DNS query types. The currently supported protocols are DNS over UDP, DNS over HTTPs, and DNS over TLS.
You may want to check out more software for Mac, such as Dynu IP Update Client, DNS Flusher or DNS Enabler, which might be similar to DNS Client.
Network Tools
Device Assistants