diff --git a/weave b/weave
index 3e954067..3e5de581 100755
--- a/weave
+++ b/weave
@@ -697,7 +697,7 @@ setup_router_iface_bridge() {
 }
 
 attach() {
-    if [ -h "$PROCFS/$CONTAINER_PID/ns/net" -a -h "/proc/$$/ns/net" -a "$(readlink $PROCFS/$CONTAINER_PID/ns/net)" = "$(readlink /proc/$$/ns/net)" ] ; then
+    if [ -h "$PROCFS/$CONTAINER_PID/ns/net" -a -h "/proc/self/ns/net" -a "$(readlink $PROCFS/$CONTAINER_PID/ns/net)" = "$(readlink /proc/self/ns/net)" ] ; then
         echo "Container is running in the host network namespace, and therefore cannot be" >&2
         echo "connected to weave. Perhaps the container was started with --net=host." >&2
         return 1