diff --git a/lib/Makefile b/lib/Makefile
index 3a90469b..1a1ffbe1 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -521,7 +521,7 @@ EXTRA_TCP_STACKS_SRCS+=		\
 	bbr.c
 endif
 
-ifdef FF_KNI
+ifndef FF_KNI
 FF_HOST_SRCS+=         \
         ff_dpdk_kni.c
 endif