diff --git a/openbsc/include/openbsc/bsc_nat_sccp.h b/openbsc/include/openbsc/bsc_nat_sccp.h
index c4f756e..eecd5dc 100644
--- a/openbsc/include/openbsc/bsc_nat_sccp.h
+++ b/openbsc/include/openbsc/bsc_nat_sccp.h
@@ -79,6 +79,7 @@
 	int con_type;
 	int con_local;
 	int imsi_checked;
+	char *imsi;
 
 	/*
 	 * audio handling. Remember if we have ever send a CRCX,
diff --git a/openbsc/src/nat/bsc_nat_utils.c b/openbsc/src/nat/bsc_nat_utils.c
index c1e3c98..9e4ccc6 100644
--- a/openbsc/src/nat/bsc_nat_utils.c
+++ b/openbsc/src/nat/bsc_nat_utils.c
@@ -469,6 +469,7 @@
 
 	ret = auth_imsi(bsc, mi_string);
 	con->imsi_checked = 1;
+	con->imsi = talloc_strdup(con, mi_string);
 	return ret;
 }