diff --git a/src/send_mulport.cc b/src/send_mulport.cc
index 09d0013..9c44852 100644
--- a/src/send_mulport.cc
+++ b/src/send_mulport.cc
@@ -53,22 +53,30 @@ class Client {
   }
 
   void Send(const T &val) {
-    clis_.at(cnt_port_)->Send(&val, sizeof(T));
+    int send_port = cnt_port_;
+    send_port = send_port % all_ports_n_;
+    clis_.at(send_port)->Send((char *)&val, sizeof(T));
     cnt_port_++;
     cnt_port_ = cnt_port_ % all_ports_n_;
   }
   void Send(const std::string &str) {
-    clis_.at(cnt_port_)->Send(str);
+    int send_port = cnt_port_;
+    send_port = send_port % all_ports_n_;
+    clis_.at(send_port)->Send(str);
     cnt_port_++;
     cnt_port_ = cnt_port_ % all_ports_n_;
   }
   void Send(const char *str, size_t size) {
-    clis_.at(cnt_port_)->Send(str, size);
+    int send_port = cnt_port_;
+    send_port = send_port % all_ports_n_;
+    clis_.at(send_port)->Send(str, size);
     cnt_port_++;
     cnt_port_ = cnt_port_ % all_ports_n_;
   }
   void Send(const char *str) {
-    clis_.at(cnt_port_)->Send(str);
+    int send_port = cnt_port_;
+    send_port = send_port % all_ports_n_;
+    clis_.at(send_port)->Send(str);
     cnt_port_++;
     cnt_port_ = cnt_port_ % all_ports_n_;
   }