Definition
Plain language
The single guarded gateway machine you have to go through to reach the important servers.
As stated in the literature
A hardened jump host that fronts a private network; SSH access to it is typically a high-value credential scope because it brokers reachability to production systems.
Also called: bastion
Why it matters: Concentrating all access through one guarded door makes monitoring far easier, but it also means stealing a key to that door hands an attacker reachability to everything behind it.
For example, an engineer who wants to restart a database server cannot connect to it directly — they first log into the single hardened gateway machine, and only from there can they reach the database.
Heard on the show
“There are two options: one principal covers two web hosts, and the other covers the web hosts plus the bastion, the production database, and the vault.”Episode 269 — How a Forged Transcript Got Model Weights Past a Safety Monitor