diff --git a/preserve-dscp/preserve-dscp.c b/preserve-dscp/preserve-dscp.c
index 8c66186..5916fc5 100644
--- a/preserve-dscp/preserve-dscp.c
+++ b/preserve-dscp/preserve-dscp.c
@@ -13,7 +13,7 @@
 
 int main(int argc, char *argv[])
 {
-	const char *filename = "preserve_dscp_kern.o";
+	char *filename = 0;
 	char *ifname_pre, *ifname_post;
 	int ifindex_pre, ifindex_post;
 	struct bpf_map *map = NULL;
@@ -26,6 +26,10 @@ int main(int argc, char *argv[])
 	DECLARE_LIBBPF_OPTS(bpf_tc_opts, attach_post);
 
 
+	if (!(filename = getenv("PRESERVE_DSCP_KERN")))
+	  filename = "preserve_dscp_kern.o";
+
+
 	if (argc < 3) {
 		fprintf(stderr, "Usage: %s <if pre> <if post> [--unload]\n", argv[0]);
 		return 1;