diff --git a/agent/test/Makefile b/agent/test/Makefile
index 5f545e4..cb70c69 100644
--- a/agent/test/Makefile
+++ b/agent/test/Makefile
@@ -30,7 +30,7 @@
 ##
 ##
 
-CXX = g++-4.9
+CXX != if [ "$(OPENOLTDEVICE)" = "phoenix" ]; then echo "g++-6"; else echo "g++-4.9"; fi
 CXXFLAGS += -g -O2
 CXXFLAGS += `pkg-config --cflags-only-I grpc++` -I/usr/local/include/pcapplusplus/
 CPPFLAGS += `pkg-config --cflags protobuf grpc`