diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
index 393aea3..e735290 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_filter.c
@@ -109,7 +109,7 @@
 	if (!hdr48)
 		return -1;
 
-	req.ctx = bsc;
+	req.ctx = con;
 	req.black_list = &bsc->nat->imsi_black_list;
 	req.access_lists = &bsc->nat->access_lists;
 	req.local_lst_name = bsc->cfg->acc_lst_name;
diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index a405763..b531c6b 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -978,10 +978,13 @@
 	}
 
 	memset(&cause, 0, sizeof(cause));
+	OSMO_ASSERT(!con->filter_state.imsi);
 	if (bsc_nat_filter_dt(bsc, msg, con, parsed, &cause) != 1) {
 		printf("FAIL: Should have passed..\n");
 		abort();
 	}
+	OSMO_ASSERT(con->filter_state.imsi);
+	OSMO_ASSERT(talloc_parent(con->filter_state.imsi) == con);
 
 	/* just some basic length checking... */
 	for (i = ARRAY_SIZE(id_resp); i >= 0; --i) {