Port knocking can be configured in a number of ways.

端口碰撞的配置方法有好多种。

youdao

Now try that again after starting the port-knocking daemon by using sudo /etc/init.

现在，使用 sudo /etc/init.d/knockd start 或 sudo knockd -d 启动端口敲门守护进程（这两个命令是等效的），然后再试一下；

youdao

Miners knocking back middies in Port Hedland yesterday had reason to cheer.

昨日在黑德兰港痛饮的矿工们有理由欢呼。

youdao

That is partly because the earthquake struck the capital, Port-au-Prince, knocking out such institutions as the country possessed.

ECONOMIST: The earthquake in Haiti

There are other opportunities knocking at the door of Chittagong port.

BBC: Bangladesh pins hope on Chittagong port