diff --git a/conf.c b/conf.c
index c8a3693..08f24be 100644
--- a/conf.c
+++ b/conf.c
@@ -1255,6 +1255,9 @@ void conf(struct ctx *c, int argc, char **argv)
 		usage(argv[0]);
 	}
 
+	if (c->pasta_conf_ns)
+		c->no_ra = 1;
+
 	if (c->mode == MODE_PASTA && c->pasta_netns_fd == -1)
 		pasta_start_ns(c);
 
diff --git a/passt.1 b/passt.1
index 65b473b..1e7cf1a 100644
--- a/passt.1
+++ b/passt.1
@@ -440,7 +440,9 @@ The default path is shown with --help.
 .TP
 .BR \-\-config-net
 Configure networking in the namespace: set up addresses and routes as configured
-or sourced from the host, and bring up the tap interface.
+or sourced from the host, and bring up the tap interface. This option implies
+\fB--no-ra\fR: the static configuration of the IPv6 address will not allow the
+kernel to set up the default route using SLAAC.
 
 .TP
 .BR \-\-ns-mac-addr " " \fIaddr