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$socket1 = @fsockopen($host, $port, $errorno, $errorstr, 5);
if($socket1 >=1) {
  echo "Online" }
else {
  echo "Offline" }                    

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uses
[...], ScktComp;

[...]

procedure CheckSocket;
var
  Client: TClientSocket;
begin
  Client := TClientSocket.Create(self);
  Client.ClientType := ctBlocking;
  Client.Host := '[IP]';
  Client.Port := [PORT];
  try
    Client.Open;
    Client.Close;
    ConnectionState := SrvOnline;
    Application.ProcessMessages;
  except
    Application.ProcessMessages;
    ConnectionState := SrvOffline;
  end;
end;