Download of Netiquette 2.3 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac app is an intellectual property of objective-see llc. Netiquette for Mac is categorized as Developer Tools. We recommend checking the downloaded files with any free antivirus.
From the developer:
Netiquette is a network monitor application that allows you to explore all network sockets and connections, either via an interactive UI, or from the command line. Netiquette is a lightweight open-source network monitor designed exclusively for macOS. Via its simple intuitive UI, you can quickly view all network connections, uncover any listening sockets, and filter and export network events.
You may want to check out more software for Mac, such as RAGE Domainer, ModelBaker or iGooMap, which might be related to Netiquette.