diff --git a/CMakeLists.txt b/CMakeLists.txt
index acfc2465..0bb4b2ec 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -620,6 +620,7 @@ set(tests
         test_shutdown_stress
         test_timeo
         test_many_sockets
+        test_diffserv
 )
 if(NOT WIN32)
 list(APPEND tests
diff --git a/src/ip.cpp b/src/ip.cpp
index 02781f11..52553c74 100644
--- a/src/ip.cpp
+++ b/src/ip.cpp
@@ -149,17 +149,13 @@ bool zmq::get_peer_ip_address (fd_t sockfd_, std::string &ip_addr_)
     return true;
 }
 
-
 void zmq::set_ip_type_of_service (fd_t s_, int iptos)
 {
-  (void) s_;
-
-  int rc = setsockopt(s_, IPPROTO_IP, IP_TOS,  &iptos, sizeof(iptos));
+    int rc = setsockopt(s_, IPPROTO_IP, IP_TOS, reinterpret_cast<const char*>(&iptos), sizeof(iptos));
 
 #ifdef ZMQ_HAVE_WINDOWS
     wsa_assert (rc != SOCKET_ERROR);
 #else
     errno_assert (rc == 0);
 #endif
-
 }