diff --git a/usr.bin/ftp/Makefile b/usr.bin/ftp/Makefile
index 89b4f7d3020f..1518dc5b2ef1 100644
--- a/usr.bin/ftp/Makefile
+++ b/usr.bin/ftp/Makefile
@@ -13,7 +13,7 @@ PROG=	ftp
 SRCS=	cmds.c cmdtab.c complete.c domacro.c fetch.c ftp.c main.c progressbar.c \
 	ruserpass.c util.c
 
-CFLAGS+=-I${.CURDIR} -I${LUKEMFTP}
+CFLAGS+=-I${.CURDIR} -I${LUKEMFTP} -DINET6
 LDADD+=	-ledit -ltermcap -lutil
 DPADD+=	${LIBEDIT} ${LIBTERMCAP} ${LIBUTIL}