遠端主機(10.64.1.129)需求：

1. 假設遠端主機打開了ssh埠
2. 啟動了PostgreSQL，且監聽埠為預設的5432
3. 遠端主機的postgreSQL DB只允許localhost訪問

本地主機(10.64.71.6)需求：

1. 安裝了pgcli
2. 啟動命令ssh -qtN -L 10.64.71.6:5432:localhost:5432 10.64.1.129

[ 其中 localhost:5432 是指遠端主機10.64.1.129上的5432和127.0.0.1的IP/host ]
在本地主機(10.64.71.6)上執行pgcli訪問遠端主機(10.64.1.129)的pg DB命令：

pgcli postgres://dtasuser:[email protected]71.6:5432/dtasdb

關於SSH -L本地轉發

SSH伺服器和應用伺服器在一起，就是本地就是本地轉發
-L [bind_address:]port:host:hostport
(man ssh)This works by allocating a socket to listen to port on the local side, optionally bound to the specified bind_address. Whenever a connection is made to this port, the connection is forwarded over the secure channel, and a connection is made to host

port hostport from the remote machine. Port forwardings can also be specified in the configuration file. IPv6 addresses can be specified by enclosing the address in square brackets. Only the superuser can forward privileged ports. By default, the local port is bound in accordance with the GatewayPorts setting. However, an explicit bind_address may be used to bind the connection to a specific address. The bind_address of “localhost” indicates that the listening port be bound for local use only, while an empty address or ‘*’ indicates that the port should be available from all interfaces.