diff --git a/src/auth.c b/src/auth.c
index 5eabeb82..edc8ef0b 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -25,6 +25,7 @@
 #include "config.h"
 
 #include <stdio.h>
+#include <string.h>
 
 #ifndef _WIN32
 #include <netinet/in.h>