diff --git a/openbsc/src/nat/bsc_nat.c b/openbsc/src/nat/bsc_nat.c
index 1799236..ffd0af1 100644
--- a/openbsc/src/nat/bsc_nat.c
+++ b/openbsc/src/nat/bsc_nat.c
@@ -225,6 +225,7 @@
 	bsc->bsc_fd.data = bsc;
 	bsc->bsc_fd.fd = ret;
 	bsc->bsc_fd.cb = ipaccess_bsc_cb;
+	bsc->bsc_fd.when = BSC_FD_READ;
 	if (bsc_register_fd(&bsc->bsc_fd) < 0) {
 		DEBUGP(DMSC, "Failed to register BSC fd.\n");
 		close(ret);