diff --git a/usr.sbin/ppp/chap_ms.c b/usr.sbin/ppp/chap_ms.c
index f4a8d90967d..c7d1480f5d9 100644
--- a/usr.sbin/ppp/chap_ms.c
+++ b/usr.sbin/ppp/chap_ms.c
@@ -36,7 +36,11 @@
 #else
 #include <sys/types.h>
 #include <stdlib.h>
+#ifdef __NetBSD__
+#include <openssl/des.h>
+#else
 #include <des.h>
+#endif
 #include <openssl/sha.h>
 #endif
 #include <md4.h>