diff --git a/src/config.c b/src/config.c
index a95d16cc..b67809b9 100644
--- a/src/config.c
+++ b/src/config.c
@@ -539,6 +539,8 @@ void merge_config(struct vpn_config *dst, struct vpn_config *src)
 		free(dst->pinentry);
 		dst->pinentry = src->pinentry;
 	}
+	if (src->tun != invalid_cfg.tun)
+		dst->tun = src->tun;
 	if (src->realm[0])
 		strcpy(dst->realm, src->realm);
 	if (src->iface_name[0])