diff --git a/server-ca/sni_challenge/Makefile b/server-ca/sni_challenge/Makefile
index b1aebfd05..ddbe51542 100644
--- a/server-ca/sni_challenge/Makefile
+++ b/server-ca/sni_challenge/Makefile
@@ -1,14 +1,14 @@
 CFLAGS+=-fpic -I/usr/include/python2.7
 LDFLAGS+=
 
-targets=sni_support.so sni_support_wrap.c sni_support.py
+targets=_sni_support.so sni_support_wrap.c sni_support.py
 
-all: sni_support.so
+all: _sni_support.so
 
 sni_support_wrap.c sni_support.py: sni_support.i
 	swig -python $^
 
-sni_support.so: sni_support_wrap.o sni_support.o
+_sni_support.so: sni_support_wrap.o sni_support.o
 	$(CC) -shared $^ -o $@
 
 clean: