The client will make both connections to the server, but one of them will be to a random high port, which would almost certainly be blocked by a firewall on the server side. 因為客戶(hù)端要和服務(wù)器端建立兩個(gè)連接,其中一個(gè)連到一個(gè)高位隨機端口,而這個(gè)端口非常有可能被服務(wù)器端的防火墻阻塞掉。