A one-way gateway changes the threat model
A path that is physically capable of sending data in only one direction removes a whole class of attack rather than mitigating it.
Nothing can come back, so remote control of the protected side is not merely unlikely but impossible through that route. It is used where the consequence justifies the inconvenience, typically industrial and defence environments, and the inconvenience is genuine: no acknowledgements, no queries, no updates by that path.
More on Architecture patterns
- A jump host concentrates administrative entryOne plank, every crossing
- A bastion should not become a general-purpose workstationIt only has the one job
- Bulkheads contain failureThe water stops at the wall
- Out-of-band management survives primary-path failureWhen the bridge is out
- A choke point makes control observableEverything through one gap
- A broker can separate clients from powerful credentialsChained to the bench