함수 is port open()

is_port_open

is_port_listen

• test set

8.8.8.8, 21 → false

8.8.8.8, 53 → true

1 Bash

IP=8.8.8.8
PORT=53
TIMEOUT=2
IS_OPEN_PORT=`nc -z -w$TIMEOUT $IP $PORT`
if [ "$IS_OPEN_PORT" = "" ]
then
	IS_OPEN_PORT=false
else
	IS_OPEN_PORT=true
fi
echo $IS_OPEN_PORT
# true

2 C#

private bool isPortOpen(string host, int port) {
   try {
       TcpClient tc = new TcpClient();
       tc.Connect(host, port);
   }
   catch {
       return false;
   }
   return true;
}

3 PHP

function is_port_open($host, $port, $timeout=2) {
  $resource = @fsockopen($host, $port, $errno, $errstr, $timeout);
  if($resource)	return true;
  return false;
}

4 See also

• is_ping
• 리눅스 로컬서버 열린 포트 확인