diff --git a/lib/cpp/src/server/TNonblockingServer.cpp b/lib/cpp/src/server/TNonblockingServer.cpp
index 649994d..8c039b9 100644
--- a/lib/cpp/src/server/TNonblockingServer.cpp
+++ b/lib/cpp/src/server/TNonblockingServer.cpp
@@ -651,9 +651,11 @@
   }
 
   #ifdef IPV6_V6ONLY
-  int zero = 0;
-  if (-1 == setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &zero, sizeof(zero))) {
-    GlobalOutput("TServerSocket::listen() IPV6_V6ONLY");
+  if (res->ai_family == AF_INET6) {
+    int zero = 0;
+    if (-1 == setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &zero, sizeof(zero))) {
+      GlobalOutput("TServerSocket::listen() IPV6_V6ONLY");
+    }
   }
   #endif // #ifdef IPV6_V6ONLY
 
diff --git a/lib/cpp/src/transport/TServerSocket.cpp b/lib/cpp/src/transport/TServerSocket.cpp
index 6b5bf05..2f14fd5 100644
--- a/lib/cpp/src/transport/TServerSocket.cpp
+++ b/lib/cpp/src/transport/TServerSocket.cpp
@@ -182,10 +182,12 @@
   #endif // #ifdef TCP_DEFER_ACCEPT
 
   #ifdef IPV6_V6ONLY
-  int zero = 0;
-  if (-1 == setsockopt(serverSocket_, IPPROTO_IPV6, IPV6_V6ONLY,
-                        &zero, sizeof(zero))) {
-    GlobalOutput.perror("TServerSocket::listen() IPV6_V6ONLY ", errno);
+  if (res->ai_family == AF_INET6) {
+    int zero = 0;
+    if (-1 == setsockopt(serverSocket_, IPPROTO_IPV6, IPV6_V6ONLY, 
+          &zero, sizeof(zero))) {
+      GlobalOutput.perror("TServerSocket::listen() IPV6_V6ONLY ", errno);
+    }
   }
   #endif // #ifdef IPV6_V6ONLY