diff --git a/src/fd_utils.c b/src/fd_utils.c
index e14fb12..6862472 100644
--- a/src/fd_utils.c
+++ b/src/fd_utils.c
@@ -7,6 +7,11 @@
 #include <sys/types.h>
 #include "ucore/fd_utils.h"
 
+/* bsd variants use TCP_KEEPALIVE */
+#if defined(TCP_KEEPALIVE) && !defined(TCP_KEEPIDLE)
+#define TCP_KEEPIDLE TCP_KEEPALIVE
+#endif
+
 int uc_set_nonblocking(int fd)
 {
     int flags = fcntl(fd,F_GETFL,NULL);