The contractor has root. The firewall lives outside.

A contractor needs a real box for six weeks: root, package installs, their own tooling. Security wants a guarantee that the box can't exfiltrate to wherever it likes.

You give them a container and add egress drop rules on the host: POST /firewall/egress, outbound 22 dropped, outbound SMTP dropped, the ranges you care about dropped. The rules are iptables on the bare metal, scoped to this container's network namespace.

Inside, the contractor runs ufw. Disables it. Flushes iptables. Installs nftables. None of it matters. Root inside the container changes nothing about rules written on the host.

A laptop-with-VPN setup makes the contractor's machine your perimeter. Here the perimeter is a rule set they can't see, on a machine they can't reach, wrapped around a shell they fully own.

Here the perimeter is a rule set they can't see, on a machine they can't reach, wrapped around a shell they fully own.