looks like a very substantive PR, thanks for putting in all this work! I don't have time to review fully right now (and I'm not a networking expert), but a few suggestions:

• is it intended to be reviewed commit-by-commit? maybe some commits could be squashed to ease review, especially if some intermediate states may be broken (I approve of granular commits in general though!)
• could some of this be split up into separate PRs? it looks like there are parts that just make some modules/tests more abstracted over various firewalls rather than assuming one implementation? so if those could be reviewed and landed separately it may be easier to get this through. similarly, the commits that are adding additional features to the module, or adding support for it in other modules, could be split out (simple "add the package to the list" commits could all go in one PR to handle that in bulk, say; not saying one commit per PR)