FreeBSD Jails And Networking
When using FreeBSD, the most common method for virtualization and process isolation are jails. Introduced with FreeBSD 4.0 in March of 2000, they predate the closest Linux equivalent, cgroups (and, by extension, Docker), by nearly a decade.
A core part of any virtualization technology is its interaction with the networking infrastructure. In this regard, I’ve found much of the available documentation lacking, often deferring to third party tools which are no longer maintained. As such, I’ve had to scrape multiple sources and reverse engineer system programs to figure out how it’s put together.