diff --git a/get_shadow_line.c b/get_shadow_line.c
index 56d2428..18b8f82 100644
--- a/get_shadow_line.c
+++ b/get_shadow_line.c
@@ -11,9 +11,8 @@
 
 #define TIMEOUT 5000
 
-static char conf_filename[] = "/etc/mxshadow.conf";
-
 static int read_config(struct sockaddr_in *addr) {
+    static const char conf_filename[] = "/etc/mxshadow.conf";
     FILE *f _cleanup_(free_file) = NULL;
     char *line _cleanup_(free_string) = NULL;
     size_t n = 0;