Explain like I'm five · Security

What is a Proxy?

Proxies, told as a story about the runner who goes to market on your behalf.

marketJimin bought two applesthe whole market knows who bought what

Go to market yourself and everyone sees your face.The whole market knows who bought what.

marketthe runnerorange hat bought two applesthe market sees only the runner; my face never leaves the castle

Send a runner, and the market sees only the runner.My face never leaves the castle.

one runneralleys to avoidmarketthe whole castle sends the same runner

A proxy is the runner who goes in your place.The whole castle sends the same runner, who keeps popular items in a basket and steers clear of bad alleys.

Hidden facethe market sees only the runner
The basketpopular items ready — a cache
Alleys to avoidno gambling alley
The ledgerwho asked for what
counter 1counter 2counter 3receptionisthands notes to whichever counter is freetownsfolk never see the castle's layout

There's a runner the other way too — the receptionist.Townsfolk can't walk into the castle; they hand notes to the receptionist, who spreads them across free counters and never reveals the layout. The note checker stands here too.

Jimin → pharmacy…medicine…a bad runner reads everythingwho you send is everythingthe runner is sicknobody can reach the marketbecause one runner does it all

The runner can read every note.Who you send is everything. A sealed note (HTTPS) can't be read, but the runner still knows where it's going. And when the runner is sick, everything stops.

In one breath

A proxy = the runner who goes in your place. The market sees only the runner, who carries a basket and a list of alleys.

A forward proxy is the castle's runner; a reverse proxy is the receptionist at the counter. The checkpoint (SWG) is a runner with a rulebook. Squid, nginx, HAProxy, Cloudflare.

When grown-ups say it

Forward proxy
The castle's runner. Goes out on my behalf. The market never sees my face.
Reverse proxy
The receptionist. Passes notes inward for the town, hiding the castle's layout.
Cache
The basket. Popular items kept ready — handed over without a trip to market.
Load balancing
Spreading notes to free counters. The receptionist shares work across counters 1, 2 and 3.
IP masking
The runner's face instead of mine. Outside sees only the runner's address. → like the sealed tunnel, minus the seal
Transparent proxy
The runner nobody asked for. The castle routes everyone through the runner automatically, unnoticed.
TLS termination
The receptionist breaks the seal. The receptionist opens sealed notes and hands them in unsealed. → breaking seals
SWG
A runner with a rulebook. The runner plus checkpoint rules. → the checkpoint to town
Next story
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