diff --git a/src/ip.cpp b/src/ip.cpp
index bc4251d3..81607656 100644
--- a/src/ip.cpp
+++ b/src/ip.cpp
@@ -167,6 +167,19 @@ void zmq::set_ip_type_of_service (fd_t s_, int 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
+
+    rc = setsockopt(
+        s_,
+        IPPROTO_IPV6,
+        IPV6_TCLASS,
+        reinterpret_cast<const char*>(&iptos),
+        sizeof(iptos));
+
 #ifdef ZMQ_HAVE_WINDOWS
     wsa_assert (rc != SOCKET_ERROR);
 #else