Docker//Port Mapping

- `-p 9999:8545` maps host port 9999 to container port 8545 — the bridge between worlds.

-p 9999:8545 maps host port 9999 to container port 8545 — the bridge between worlds.

Without -p, a container's ports are invisible from the host.

Not a security hole — acts as a controlled bridge for one specific port+container, rest stays isolated.

-p is for network, -v is for files — both bridge host↔container but in different dimensions.

Only expose what's needed: if one node needs RPC access, only map that node's port.