Multipass: Add a section for Linux under "How to troubleshoot networking"

Context

Multipass docs are in reasonably good shape, but there are (as always) little things that could be improved to offer a better user experience.

Multipass docs are maintained in and published from the Ubuntu Discourse forum. To suggest changes in a Discourse-hosted docs page, scroll all the way down to the bottom of the page and open the page to which the "Help improve this document in the forum" link points. On the Discourse page, scroll to the bottom of the article (if there are comments, then the bottom of the article is just where the comments start, i.e. not at the very bottom of the page) and click "Edit". (You need an account on Ubuntu Discourse.) See also: Contribute to Multipass docs.

Task

The How to troubleshoot networking guide is missing a Linux section. To create it, you could leverage your own experience using Multipass on Linux, scrape recent bug reports on the Multipass GitHub for user-reported troubles and solutions, or include potential issues suggested by our dev team such as lingering dnsmasq & subnet clashes.

This task requires some level of familiarity with networking concepts and common issues, as well as experience using Multipass on Linux.

Useful links

Before you get started, make sure to review the main concepts of the Diátaxis documentation framework and also check the Canonical Documentation Style Guide.

If you are new to the Canonical Open Documentation Academy, you may also want to review our Getting Started topic on the Ubuntu Discourse forum.