diff --git a/js/xpconnect/src/xpc.msg b/js/xpconnect/src/xpc.msg
index 80cdc7a748d3..8548d9b7aad5 100644
--- a/js/xpconnect/src/xpc.msg
+++ b/js/xpconnect/src/xpc.msg
@@ -166,6 +166,7 @@ XPC_MSG_DEF(NS_ERROR_DNS_LOOKUP_QUEUE_FULL          , "The DNS lookup queue is f
 XPC_MSG_DEF(NS_ERROR_UNKNOWN_PROXY_HOST             , "The lookup of the proxy hostname failed")
 XPC_MSG_DEF(NS_ERROR_UNKNOWN_SOCKET_TYPE            , "The specified socket type does not exist")
 XPC_MSG_DEF(NS_ERROR_SOCKET_CREATE_FAILED           , "The specified socket type could not be created")
+XPC_MSG_DEF(NS_ERROR_SOCKET_ADDRESS_NOT_SUPPORTED   , "The specified socket address type is not supported")
 XPC_MSG_DEF(NS_ERROR_CACHE_KEY_NOT_FOUND            , "Cache key could not be found")
 XPC_MSG_DEF(NS_ERROR_CACHE_DATA_IS_STREAM           , "Cache data is a stream")
 XPC_MSG_DEF(NS_ERROR_CACHE_DATA_IS_NOT_STREAM       , "Cache data is not a stream")
diff --git a/netwerk/base/src/nsSocketTransport2.cpp b/netwerk/base/src/nsSocketTransport2.cpp
index 14313eed8ab6..bf5f6dfd7a41 100644
--- a/netwerk/base/src/nsSocketTransport2.cpp
+++ b/netwerk/base/src/nsSocketTransport2.cpp
@@ -160,10 +160,12 @@ ErrorAccordingToNSPR(PRErrorCode errorCode)
     case PR_ADDRESS_NOT_AVAILABLE_ERROR:
     // Treat EACCES as a soft error since (at least on Linux) connect() returns
     // EACCES when an IPv6 connection is blocked by a firewall. See bug 270784.
-    case PR_ADDRESS_NOT_SUPPORTED_ERROR:
     case PR_NO_ACCESS_RIGHTS_ERROR:
         rv = NS_ERROR_CONNECTION_REFUSED;
         break;
+    case PR_ADDRESS_NOT_SUPPORTED_ERROR:
+        rv = NS_ERROR_SOCKET_ADDRESS_NOT_SUPPORTED;
+        break;
     case PR_IO_TIMEOUT_ERROR:
     case PR_CONNECT_TIMEOUT_ERROR:
         rv = NS_ERROR_NET_TIMEOUT;
diff --git a/xpcom/base/ErrorList.h b/xpcom/base/ErrorList.h
index 31f554d67ad3..639c5558d030 100644
--- a/xpcom/base/ErrorList.h
+++ b/xpcom/base/ErrorList.h
@@ -251,7 +251,8 @@
   ERROR(NS_ERROR_UNKNOWN_SOCKET_TYPE,   FAILURE(51)),
   /* The specified socket type could not be created. */
   ERROR(NS_ERROR_SOCKET_CREATE_FAILED,  FAILURE(52)),
-
+  /* The operating system doesn't support the given type of address. */
+  ERROR(NS_ERROR_SOCKET_ADDRESS_NOT_SUPPORTED, FAILURE(53)),
 
   /* Cache specific error codes: */
   ERROR(NS_ERROR_CACHE_KEY_NOT_FOUND,        FAILURE(61)),